- The rate of placental transfer by simple diffusion is most dependent on the lipid solubility of the drug. Lipid-soluble, non-ionized drugs cross the placenta readily, while water-soluble, ionized drugs cross poorly. Molecular weight, protein binding, and blood flow also influence transfer but lipid solubility is the primary determinant for passive diffusion.
- Fetal hydantoin syndrome, associated with phenytoin use in pregnancy, includes craniofacial abnormalities such as cleft lip and palate, microcephaly, and nail hypoplasia. Neural tube defects are more associated with valproate, while congenital heart disease is linked to lithium. Phenytoin is classified as FDA Category D in pregnancy.
- Doxylamine with pyridoxine (Vitamin B6) is the first-line antiemetic for nausea and vomiting in early pregnancy, with a well-established safety profile. Ondansetron has been associated with a small increased risk of cleft palate in some studies. Metoclopramide and prochlorperazine are second-line options.
- Atosiban is a competitive antagonist of oxytocin receptors, inhibiting oxytocin-induced uterine contractions. It is used as a tocolytic agent with fewer cardiovascular side effects compared to beta-agonists like ritodrine. Nifedipine is a calcium channel blocker, indomethacin is a COX inhibitor, and magnesium sulphate acts as a calcium antagonist at the cellular level.
- Betamethasone is the preferred corticosteroid for antenatal therapy to accelerate fetal lung maturity, typically given as two doses of 12 mg intramuscularly 24 hours apart. It reduces the incidence of neonatal respiratory distress syndrome, intraventricular haemorrhage, and necrotising enterocolitis. Dexamethasone is an alternative but betamethasone is more widely used in obstetric practice.
- Insulin is the gold standard for glycaemic control in pregnancy because it does not cross the placenta significantly and allows precise dose titration. While metformin is increasingly used in gestational diabetes, the preconception period is best managed with insulin to optimise glycaemic control and minimise teratogenic risks. Sulfonylureas like glibenclamide cross the placenta and are not first-line in pregnancy.
- Tamoxifen, a selective oestrogen receptor modulator (SERM), significantly increases the risk of venous thromboembolism (VTE) including deep vein thrombosis and pulmonary embolism. It also increases the risk of endometrial hyperplasia and carcinoma. Pulmonary fibrosis is associated with bleomycin, and cardiomyopathy is associated with anthracyclines like doxorubicin.
- Oxytocin is the first-line agent for the management of postpartum haemorrhage due to uterine atony. It is administered as a slow intravenous infusion and causes sustained rhythmic contractions of the uterus. Ergometrine is a second-line agent but is contraindicated in hypertension. Carboprost (15-methyl prostaglandin F2α) and misoprostol are also used as second-line therapies.
- Labetalol, a combined alpha- and beta-blocker, is the first-line agent for acute management of severe hypertension in pregnancy due to its rapid onset and favourable safety profile. Nifedipine (short-acting) and hydralazine are alternatives, but labetalol is preferred. Methyldopa is used for chronic hypertension management. ACE inhibitors like captopril are contraindicated in pregnancy due to fetotoxicity.
- Azathioprine is considered the safest immunosuppressant among these options in pregnancy, though it crosses the placenta, the fetal liver lacks the enzyme to convert it to its active metabolite. Methotrexate, mycophenolate, cyclophosphamide, and leflunomide are highly teratogenic and contraindicated in pregnancy.
- Magnesium sulphate therapy for eclampsia can lead to magnesium toxicity, with respiratory depression being the most serious concern. Deep tendon reflexes are lost at serum magnesium levels around 10 mg/dL, and respiratory depression occurs at higher levels (12-15 mg/dL). Calcium gluconate is the antidote. Monitoring of reflexes, respiratory rate, and urine output is essential.
- Nephrotoxicity is the dose-limiting toxicity of cisplatin, characterised by acute kidney injury, hypomagnesaemia, and hypokalaemia. Adequate hydration and diuresis are essential protective measures. Ototoxicity (tinnitus and high-frequency hearing loss) is also common, but nephrotoxicity limits the cumulative dose. Cardiotoxicity is associated with doxorubicin.
- Breakthrough bleeding on the COCP is most commonly due to inadequate oestrogen dose, which fails to provide sufficient endometrial stabilisation. Oestrogen promotes endometrial proliferation and stability. Increasing the oestrogen dose or switching to a formulation with a different progestogen can help. If the progestogen dose is too high, it may cause atrophy and also lead to spotting.
- The copper intrauterine device (Cu-IUD) is the most effective method of emergency contraception, effective up to 5 days after unprotected intercourse with a failure rate of less than 1%. Ulipristal acetate (30 mg) is more effective than levonorgestrel and is effective up to 120 hours (5 days) after intercourse. However, the Cu-IUD remains the most effective overall.
- GnRH agonists (e.g., leuprolide, goserelin) cause an initial flare in gonadotrophin release followed by pituitary downregulation, leading to a hypo-oestrogenic state. The most common adverse effects are vasomotor symptoms (hot flushes), vaginal dryness, and bone mineral density loss. Add-back hormone therapy (oestrogen + progestogen) is often used to mitigate these effects for prolonged treatment.
- Nitrofurantoin is safe and commonly used for urinary tract infections in pregnancy, particularly in the second trimester. Ciprofloxacin (fluoroquinolone) is avoided due to concerns about arthropathy in the fetus. Doxycycline is contraindicated in pregnancy as tetracyclines cause discolouration of fetal teeth and bone growth impairment. Sulfamethoxazole-trimethoprim should be avoided near term due to the risk of kernicterus.
- Tenofovir is a nucleotide reverse transcriptase inhibitor used in chronic hepatitis B. It is safe in pregnancy (FDA Category B) and reduces viral load, thereby decreasing the risk of perinatal transmission. Interferon-alpha is not used in pregnancy due to its antiproliferative effects. Ribavirin is teratogenic. Acyclovir is for herpes viruses, not hepatitis B.
- Warfarin is teratogenic (FDA Category X), causing fetal warfarin syndrome (nasal hypoplasia, stippled epiphyses) especially between 6-12 weeks gestation. The recommended approach is to switch to LMWH before conception and continue throughout pregnancy, with dose adjustments based on anti-Xa levels. LMWH does not cross the placenta and is safe for the fetus.
- The copper intrauterine device (Cu-IUD) is a non-hormonal method with efficacy that is not affected by body weight or BMI. Hormonal methods, including the COCP, POP, contraceptive implant, and DMPA, may have reduced efficacy in women with higher BMI due to altered pharmacokinetics. The Cu-IUD provides highly reliable long-term contraception independent of user weight.
- Metformin is increasingly used in gestational diabetes and is considered safe in pregnancy (FDA Category B). It does not cause hypoglycaemia and improves insulin sensitivity. While glibenclamide is sometimes used, it crosses the placenta and has been associated with larger birth weight. Rosiglitazone, sitagliptin (DPP-4 inhibitor), and acarbose have limited safety data in pregnancy.
- Lamotrigine clearance significantly increases during pregnancy due to increased hepatic glucuronidation, leading to a marked decrease in serum concentrations. This can result in breakthrough seizures if doses are not increased. Monitoring of serum lamotrigine levels and dose adjustment throughout pregnancy and postpartum are essential.
- Paclitaxel, a taxane that stabilises microtubules, commonly causes peripheral sensory neuropathy, which is dose-dependent and cumulative. It is administered with premedication (steroids and antihistamines) to prevent hypersensitivity reactions. Haemorrhagic cystitis is associated with cyclophosphamide, nephrotoxicity with cisplatin, and cardiotoxicity with doxorubicin.
- Penicillins such as amoxicillin are considered safe during breastfeeding, with minimal excretion into breast milk and no known adverse effects on the infant. Tetracyclines should be avoided as they can cause dental discolouration in the nursing infant. Ciprofloxacin is relatively contraindicated due to concerns about arthropathy, and chloramphenicol carries a risk of grey baby syndrome.
- Carboplatin, like cisplatin, is a platinum-based alkylating agent that forms intrastrand and interstrand DNA cross-links, thereby inhibiting DNA replication and transcription. Carboplatin is less nephrotoxic and emetogenic than cisplatin but causes more myelosuppression, particularly thrombocytopenia. Topoisomerase II inhibition is the mechanism of etoposide, and microtubule stabilisation is the mechanism of paclitaxel.
- Clomiphene citrate is a selective oestrogen receptor modulator (SERM) that acts as an antagonist at oestrogen receptors in the hypothalamus, blocking negative feedback and thereby increasing GnRH pulsatility. This leads to increased pituitary FSH and LH secretion, stimulating follicular development. Letrozole (an aromatase inhibitor) has a different mechanism, inhibiting oestrogen synthesis.
- Rifampicin is safe in pregnancy and is a cornerstone of anti-tuberculous therapy. Isoniazid is also safe but requires pyridoxine (Vitamin B6) supplementation to prevent peripheral neuropathy. Ethambutol is generally considered safe. Streptomycin, an aminoglycoside, is contraindicated in pregnancy due to the risk of fetal ototoxicity (eighth cranial nerve damage). Pyrazinamide has less safety data but is used when necessary.
- Cetrorelix is a GnRH antagonist used in controlled ovarian hyperstimulation for IVF to prevent premature LH surge. Unlike GnRH agonists (leuprolide, goserelin, nafarelin, triptorelin), antagonists cause immediate suppression of gonadotrophins without an initial flare effect. This allows a shorter treatment cycle and reduced gonadotrophin requirements.
- Folinic acid (calcium folinate) is the specific antidote for methotrexate toxicity. It bypasses the dihydrofolate reductase blockade caused by methotrexate, providing the reduced folate required for DNA synthesis. Folic acid itself cannot be used as it requires dihydrofolate reductase for conversion to its active form. Folinic acid rescue is standard after high-dose methotrexate therapy.
- Levonorgestrel, a second-generation progestogen, is associated with the lowest risk of venous thromboembolism (VTE) among the common progestogens used in COCPs. Third-generation progestogens (desogestrel, gestodene) and drospirenone carry a slightly higher VTE risk. Cyproterone acetate, used in Dianette, carries a higher VTE risk and is not recommended solely for contraception.
- Anti-factor Xa assay is the recommended method for monitoring LMWH therapy when monitoring is required (e.g., in pregnancy, extremes of body weight, or renal impairment). LMWH has a predictable dose-response relationship and generally does not require routine monitoring, but pregnancy alters pharmacokinetics, necessitating periodic anti-Xa level monitoring to ensure adequate dosing.
- Doxorubicin, an anthracycline antibiotic, causes cumulative dose-dependent cardiotoxicity characterised by dilated cardiomyopathy and heart failure. The cumulative lifetime dose is typically limited to 450-550 mg/m². Dexrazoxane is a cardioprotectant that can be used. Haemorrhagic cystitis is associated with cyclophosphamide, and pulmonary fibrosis with bleomycin.
- Propylthiouracil (PTU) is preferred over carbimazole in the first trimester of pregnancy due to the association of carbimazole with aplasia cutis congenita (scalp defect) in the fetus. PTU is also more highly protein-bound, reducing placental transfer. Radioactive iodine is absolutely contraindicated in pregnancy as it destroys the fetal thyroid gland.
- The primary mechanism of the progesterone-only pill (POP) is thickening of cervical mucus, making it impenetrable to sperm, and induction of endometrial atrophy, which may prevent implantation. Unlike the COCP, the POP does not consistently suppress ovulation in all cycles; about 40-60% of cycles remain ovulatory. Consistent daily intake is critical for effectiveness.
- Ulipristal acetate is a selective progesterone receptor modulator (SPRM) that exerts tissue-specific agonist, antagonist, or mixed effects on progesterone receptors. It reduces fibroid size by inhibiting cell proliferation and inducing apoptosis. It is also used for emergency contraception. GnRH agonists (e.g., leuprolide) and antagonists (e.g., cetrorelix) work via different mechanisms.
- The management of severe OHSS involves volume expansion with intravenous fluids and human albumin to maintain intravascular volume and improve renal perfusion. Diuretics like furosemide are contraindicated as they worsen haemoconcentration and hypovolaemia. Dopamine at low doses has been used but albumin with crystalloids is the mainstay. The underlying pathophysiology is increased capillary permeability.
- Oral metronidazole is the recommended treatment for bacterial vaginosis in pregnancy to reduce the risk of preterm birth, particularly in high-risk women. Although topical preparations are effective for symptomatic relief, oral therapy achieves better tissue penetration and is preferred in pregnancy. Doxycycline is contraindicated in pregnancy and tetracyclines are avoided.
- The combined oral contraceptive pill (COCP) is contraindicated in women with a history of venous thromboembolism (VTE) due to the oestrogen component, which increases the risk of thrombotic events. Progestogen-only methods (POP, implant, LNG-IUS) and the copper IUD are safe alternatives as they do not increase VTE risk.
- Inhaled short-acting beta-agonists like salbutamol are the first-line acute treatment for asthma exacerbation in pregnancy, as in non-pregnant patients. Inhaled route delivers the drug directly to the airways with minimal systemic absorption, making it safe in pregnancy. Systemic corticosteroids may be added for severe exacerbations but inhaled beta-agonists are the priority.
- Long-term use of DMPA is associated with decreased bone mineral density due to suppression of oestradiol levels. The bone loss is partially reversible after discontinuation. DMPA is an effective contraceptive with the convenience of once-every-13-week administration. It does not increase VTE risk (unlike COCP) and does not cause ovarian failure or endometrial hyperplasia.
- Megestrol acetate is a synthetic progestogen used in the treatment of advanced or recurrent endometrial cancer. It acts by opposing the proliferative effects of oestrogen on the endometrium, inducing secretory transformation and eventually atrophy. Progestogens are effective in hormone-sensitive endometrial cancers, particularly those that are well-differentiated and oestrogen receptor-positive.
- Intravenous benzylpenicillin (Penicillin G) is the preferred agent for intrapartum GBS prophylaxis, with a loading dose followed by maintenance doses every 4 hours until delivery. Intravenous administration ensures adequate fetal serum levels. Clindamycin is reserved for women with severe penicillin allergy. Oral antibiotics are inadequate for intrapartum prophylaxis due to unpredictable absorption.
- Fluconazole is excreted into breast milk in low concentrations and is considered compatible with breastfeeding. It is commonly used for vaginal candidiasis during lactation. Ketoconazole and itraconazole have limited data but are generally avoided. Griseofulvin is contraindicated as it has been associated with hepatotoxicity in nursing infants. Amphotericin B is poorly absorbed orally.
- Codeine is a prodrug that is metabolised by CYP2D6 into morphine. Genetic variability in CYP2D6 activity (ultra-rapid metabolisers) can lead to high levels of morphine, posing a risk of neonatal respiratory depression and opioid withdrawal. Paracetamol and low-dose ibuprofen (avoid in third trimester) are preferred for pain relief in pregnancy.
- Aprepitant is a neurokinin-1 (NK1) receptor antagonist that blocks substance P, a key neurotransmitter in the emetic pathway. It is used in combination with a 5-HT3 antagonist (ondansetron) and dexamethasone for highly emetogenic chemotherapy regimens, such as those containing cisplatin. Ondansetron is a 5-HT3 antagonist, and metoclopramide is a dopamine D2 antagonist.
- Valproate carries the highest risk of major congenital malformations (especially neural tube defects) among antiepileptic drugs, with a dose-dependent relationship. Additionally, it is associated with neurodevelopmental delay and reduced IQ in children exposed in utero. It should be avoided in pregnancy when possible, and women of childbearing potential should use effective contraception.
- Raloxifene is a second-generation selective oestrogen receptor modulator (SERM) with oestrogen-agonist effects on bone (increasing bone mineral density) and oestrogen-antagonist effects on breast and endometrial tissue. Unlike tamoxifen, which stimulates the endometrium, raloxifene does not increase endometrial cancer risk. It reduces the risk of vertebral fractures in postmenopausal osteoporosis.
- Methyldopa is metabolised to alpha-methylnorepinephrine, which acts as an agonist at central alpha-2 adrenergic receptors in the brainstem, reducing sympathetic outflow and decreasing peripheral vascular resistance. It is the preferred first-line antihypertensive for chronic hypertension in pregnancy due to its extensive safety record. It does not significantly reduce uteroplacental blood flow.
- Irregular menstrual bleeding, including prolonged spotting, oligomenorrhoea, or amenorrhoea, is the most common adverse effect leading to discontinuation of the etonogestrel implant. This unpredictable bleeding pattern occurs due to the progestin-induced endometrial suppression and atrophy. The pattern stabilises over time but can be bothersome enough for women to request removal.
- Aggressive intravenous hydration before and after cisplatin administration is essential to prevent nephrotoxicity, which is the dose-limiting toxicity of cisplatin. Hydration with normal saline and maintenance of high urine output helps reduce the concentration of cisplatin in the renal tubules, thereby minimising tubular damage. Mannitol may also be added to promote diuresis.
- Metoclopramide can be administered intravenously and is commonly used in the hospital management of hyperemesis gravidarum. It is a dopamine D2 receptor antagonist with prokinetic properties. While doxylamine and pyridoxine are first-line, they are only available in oral formulations. Cyclizine and prochlorperazine are options but metoclopramide is preferred for IV use.
- The copper intrauterine device causes a sterile local inflammatory reaction in the endometrium, characterised by infiltration of leukocytes and prostaglandin release. This inflammatory response alters endometrial vascularity and can lead to increased menstrual blood loss and dysmenorrhoea. The levonorgestrel-releasing IUS (Mirena) has the opposite effect, reducing menstrual bleeding.
- Gentamicin, an aminoglycoside, is primarily excreted unchanged by the kidneys and requires dose adjustment in renal impairment to avoid ototoxicity and nephrotoxicity. Therapeutic drug monitoring is recommended. Nitrofurantoin is contraindicated if eGFR is less than 30 mL/min due to accumulation and risk of peripheral neuropathy. Amoxicillin and cefalexin require adjustment only in severe impairment.
- The standard treatment for antiphospholipid syndrome in pregnancy is a combination of low molecular weight heparin (LMWH) and low-dose aspirin (75 mg daily). This regimen significantly improves pregnancy outcomes, including live birth rates, by preventing thrombotic events at the placental level. Warfarin is teratogenic and avoided. Prednisolone and IVIG are reserved for refractory cases.
- Carbamazepine is an enzyme-inducing antiepileptic drug that accelerates folate metabolism, increasing the risk of folate deficiency and neural tube defects. Women on carbamazepine (and valproate) should receive high-dose folic acid (5 mg daily) preconception and in the first trimester. Vitamin D may also be affected but the most critical supplementation is folic acid.
- Smoking in women aged 35 years or older is an absolute contraindication (UKMEC 4) to COCP use due to the significantly increased risk of cardiovascular events, including myocardial infarction and stroke. BMI of 30 kg/m² (UKMEC 2) and migraine without aura (UKMEC 2) are relative contraindications. Family history of breast cancer and varicose veins are not contraindications.
- Pegylated liposomal doxorubicin has a favourable toxicity profile with reduced cardiotoxicity compared to conventional doxorubicin. The liposomal encapsulation alters the pharmacokinetics, prolonging circulation time and allowing preferential accumulation in tumour tissue. While hand-foot syndrome (palmar-plantar erythrodysesthesia) is more common, cardiac risk is significantly reduced, allowing higher cumulative doses.
- Intramuscular benzathine penicillin G is the treatment of choice for syphilis in pregnancy, as it effectively treats the mother and prevents congenital syphilis in the fetus. Doxycycline is contraindicated in pregnancy. Ceftriaxone and azithromycin are alternatives but penicillin remains first-line. Intravenous penicillin G is used for neurosyphilis.
- Danazol is a synthetic androgen derivative that suppresses gonadotrophins and creates a hypo-oestrogenic environment. Its use is limited by androgenic side effects including hirsutism, deepening of the voice, acne, and weight gain. These side effects can be irreversible, particularly voice changes, which limits its long-term use. GnRH agonists have largely replaced danazol in clinical practice.
- The combined oral contraceptive pill (COCP) has been consistently shown to reduce the risk of ovarian cancer by approximately 40-50% with long-term use, and the protective effect persists for decades after discontinuation. The mechanism is thought to be suppression of ovulation, reducing epithelial trauma and inflammation. Tamoxifen reduces breast cancer risk but not ovarian cancer.
- Aztreonam is a monobactam antibiotic with activity against gram-negative bacteria and minimal cross-reactivity with penicillins, making it a safe option in true penicillin allergy. Ceftriaxone (cephalosporin) has some cross-reactivity risk. Ciprofloxacin is relatively contraindicated in pregnancy. Gentamicin may be used but requires monitoring. Nitrofurantoin does not achieve adequate renal tissue levels for pyelonephritis.
- In women at high risk of OHSS, a GnRH agonist (e.g., buserelin, triptorelin) is used as the trigger for final oocyte maturation instead of hCG. The GnRH agonist causes an endogenous LH surge from the pituitary, which is shorter in duration and reduces the risk of OHSS compared to exogenous hCG. This is only possible in GnRH antagonist protocols.
- Lithium has a narrow therapeutic index (0.6-1.2 mmol/L) and toxicity occurs at levels above 1.5 mmol/L. Regular monitoring of serum lithium levels is essential, along with renal and thyroid function tests. However, serum drug level monitoring is the most critical for dose adjustment and preventing toxicity. Signs of toxicity include tremor, ataxia, confusion, and seizures.
- Acyclovir is the most studied antiviral for herpes simplex virus in pregnancy and has a well-established safety profile. It is used for primary or recurrent genital herpes to reduce the duration and severity of symptoms and to suppress viral shedding. Valacyclovir is also safe but acyclovir has the most safety data. Ganciclovir and foscarnet are reserved for life-threatening CMV and are not used in pregnancy.
- Tranexamic acid is an antifibrinolytic agent that competitively inhibits the activation of plasminogen to plasmin, thereby preventing fibrin clot breakdown. It reduces menstrual blood loss by approximately 40-50% in women with menorrhagia. It is also used in trauma and postpartum haemorrhage. It does not affect clotting factor synthesis or platelet function.
- Febrile neutropenia is an oncological emergency requiring immediate hospitalisation and intravenous broad-spectrum antibiotics after appropriate cultures. The most common pathogens are gram-negative bacilli. G-CSF may be used as adjunctive therapy or prophylaxis in subsequent cycles but does not replace the need for urgent antibiotics. Dose reduction may be considered for future cycles.
- Prednisolone is the preferred systemic corticosteroid in pregnancy because it is extensively metabolised to inactive forms by placental 11-beta-hydroxysteroid dehydrogenase type 2, limiting fetal exposure. Dexamethasone and betamethasone are less effectively metabolised by the placenta and result in higher fetal concentrations. They are specifically used for fetal lung maturation when indicated.
- Trastuzumab (Herceptin) is a humanised monoclonal antibody that targets the HER2/neu (ErbB2) receptor, which is overexpressed in approximately 20% of breast cancers. It inhibits downstream signalling pathways, leading to cell cycle arrest and antibody-dependent cellular cytotoxicity. It is associated with cardiotoxicity, particularly when combined with anthracyclines. Bevacizumab targets VEGF.
- Infliximab, a monoclonal antibody (IgG1), crosses the placenta minimally in the first trimester but increasingly after 20 weeks gestation due to active transport via FcRn receptors. It is generally considered safe to continue in pregnancy for women with moderate-to-severe Crohn's disease. Infants exposed in utero may have detectable drug levels for several months, and live vaccines should be avoided for the first 6 months of life.
- The LNG-IUS releases levonorgestrel locally into the endometrial cavity, causing profound endometrial suppression with glandular atrophy and stromal decidualisation. This leads to a thin, inactive endometrium, which is the mechanism for treating endometrial hyperplasia and reducing menstrual bleeding. The systemic hormone levels are low, minimising systemic progestogenic side effects.
- Cabergoline is a long-acting dopamine D2 receptor agonist that suppresses prolactin secretion by the anterior pituitary lactotroph cells. By binding to dopamine receptors on lactotrophs, it inhibits prolactin synthesis and release, restoring ovulatory cycles and fertility. It is more effective and better tolerated than bromocriptine, with fewer gastrointestinal side effects and once- or twice-weekly dosing.
- Levothyroxine (T4) replacement is the standard treatment for hypothyroidism in pregnancy. Maintaining euthyroid status is critical for fetal neurodevelopment, particularly in the first trimester when the fetus is entirely dependent on maternal thyroid hormone. Women with hypothyroidism typically require a 30-50% dose increase in pregnancy due to increased volume of distribution and placental transfer of T4.
- Epidemiological studies have shown that high-dose fluconazole (400-800 mg daily) in the first trimester may be associated with an increased risk of fetal abnormalities, including craniosynostosis and cardiac defects. However, single low-dose fluconazole (150 mg) for vaginal candidiasis is generally considered low risk. Women trying to conceive should be counselled appropriately, and single-dose therapy is acceptable if indicated.
- Carboplatin dosing is calculated using the Calvert formula: Dose (mg) = target AUC × (GFR + 25). Unlike cisplatin, carboplatin is primarily excreted renally, and its dose must be adjusted for renal function to avoid excessive myelosuppression (particularly thrombocytopenia). The target AUC is typically 5-7.5 depending on the treatment protocol. Body surface area-based dosing is used for most other chemotherapeutic agents.
- The COCP reduces menstrual blood loss by providing a stable hormonal environment that suppresses endometrial proliferation. The oestrogen component stabilises the endometrium, while the progestogen component causes a thin, atrophic endometrium. This results in lighter, more predictable withdrawal bleeds. The reduction in menstrual blood loss is approximately 40-50% in women with menorrhagia.
- Erythromycin (a macrolide antibiotic) is used in PPROM to prolong pregnancy and reduce neonatal morbidity, particularly the incidence of neonatal infection, intraventricular haemorrhage, and necrotising enterocolitis. The ORACLE trial demonstrated benefits of erythromycin in PPROM. Co-amoxiclav is avoided due to an increased risk of neonatal necrotising enterocolitis.
- Misoprostol (a prostaglandin E1 analogue) can be used as an alternative or adjunct to oxytocin for cervical ripening and uterine evacuation in molar pregnancy. It is particularly useful when oxytocin is ineffective. However, caution is needed as prostaglandins may increase the risk of trophoblastic embolisation in complete molar pregnancies. Surgical evacuation remains the primary treatment.
- Oestrogen-only hormone replacement therapy is appropriate for women who have undergone hysterectomy and bilateral salpingo-oophorectomy, as there is no risk of endometrial cancer. Combined therapy is required only for women with an intact uterus to prevent endometrial hyperplasia. Tibolone is a synthetic steroid with oestrogenic, progestogenic, and androgenic activities but is not first-line.
- Misoprostol (prostaglandin E1 analogue) is the standard medication for medical management of incomplete miscarriage and first-trimester termination of pregnancy. It causes cervical ripening and uterine contractions, leading to expulsion of products of conception. Oxytocin is less effective in the first trimester due to lower oxytocin receptor density. Mifepristone (an antiprogestogen) can be used in combination with misoprostol for medical abortion.
- Mood changes are a recognised side effect of the COCP, particularly related to the progestogen component. Switching to a formulation with a different progestogen, such as one with a lower androgenic profile (e.g., drospirenone with its anti-mineralocorticoid properties), may improve mood symptoms. If symptoms persist, alternative non-hormonal contraception should be considered.
- Imiquimod is an immune response modifier that acts as a Toll-like receptor 7 (TLR7) agonist, stimulating the innate immune system. It induces production of interferon-alpha, tumour necrosis factor-alpha, and other cytokines, thereby enhancing the local immune response against viral infections and neoplastic cells. It is used topically for vulval warts, vulval intraepithelial neoplasia (VIN), and superficial basal cell carcinoma.
- Fentanyl is a synthetic opioid with a rapid onset and short duration of action (half-life approximately 2-4 hours), making it suitable for labour analgesia with minimal neonatal respiratory depression if carefully timed. Pethidine has a longer half-life and its metabolite, norpethidine, can accumulate in the neonate, causing prolonged respiratory depression. Morphine also has a longer duration of action.
- Letrozole is a third-generation aromatase inhibitor that reversibly inhibits the aromatase enzyme, blocking the conversion of androgens to oestrogens in peripheral tissues. The reduction in oestrogen levels reduces negative feedback on the hypothalamus and pituitary, leading to increased FSH secretion and follicular development. It has largely replaced clomiphene citrate as first-line ovulation induction due to better pregnancy rates and lower risk of multiple pregnancy.
- Therapeutic LMWH should be discontinued approximately 24 hours before planned induction of labour or caesarean section to allow clearance of the anticoagulant effect and reduce the risk of bleeding complications. Regional anaesthesia (neuraxial blockade) should not be administered within 24 hours of the last therapeutic dose of LMWH. Prophylactic LMWH may be stopped 12 hours prior.
- Prednisolone (oral corticosteroid) is the preferred treatment for acute gout in pregnancy, as it is safe and effective. NSAIDs like indomethacin should be avoided, particularly in the third trimester, due to the risk of premature closure of the ductus arteriosus and oligohydramnios. Colchicine has limited safety data. Allopurinol and febuxostat are urate-lowering therapies for chronic management, not acute attacks.
- Letrozole is an aromatase inhibitor that is effective only in postmenopausal women, as it works by inhibiting peripheral conversion of androgens to oestrogens. In premenopausal women, the ovaries produce sufficient aromatase to overcome the blockade. Therefore, premenopausal women require ovarian suppression (e.g., with GnRH agonists) or oophorectomy before aromatase inhibitor therapy. Tamoxifen is used in premenopausal women.
- Intramuscular adrenaline (epinephrine) is the first-line treatment for anaphylaxis in pregnancy, as in non-pregnant patients. Adrenaline causes vasoconstriction, bronchodilation, and reduces oedema. It should be administered immediately into the anterolateral thigh. Pregnant women should be positioned in left lateral tilt to prevent aortocaval compression. Antihistamines and corticosteroids are second-line adjunctive therapies.
- Disulfiram is contraindicated in pregnancy (FDA Category C) and should be discontinued before conception. Animal studies have shown teratogenic effects, including limb defects and neural tube abnormalities. There is limited human data, but the potential risks outweigh benefits in pregnancy. Alcohol cessation counselling and alternative strategies for maintaining abstinence should be discussed.
- Cabergoline should be discontinued as soon as pregnancy is confirmed, as the safety of continuous use throughout pregnancy has not been established. The risk of prolactinoma expansion during pregnancy is low for microadenomas. However, in women with macroadenomas, cabergoline may be cautiously continued under specialist supervision. Bromocriptine has more safety data in pregnancy but is less well-tolerated.
- Cisplatin is the most common chemotherapeutic agent used as a radiosensitiser in gynaecological cancers, particularly cervical cancer. It enhances the effects of radiation by inhibiting DNA repair after radiation-induced damage. Concurrent cisplatin chemoradiation is the standard of care for locally advanced cervical cancer. This approach improves local control and overall survival compared to radiation alone.
- Nitrofurantoin (50-100 mg at night) is the preferred antibiotic for UTI prophylaxis in pregnancy due to its efficacy against common uropathogens, minimal impact on gut flora, and established safety profile. It achieves high urinary concentrations with low systemic absorption. Trimethoprim is avoided in the first trimester (folate antagonist) and near term (kernicterus risk). Fluoroquinolones and tetracyclines are avoided in pregnancy.
- The LNG-IUS releases levonorgestrel locally into the endometrial cavity, with minimal systemic absorption. The systemic hormone levels are significantly lower than with oral progestogens, which is why ovulation is not consistently suppressed and systemic side effects are minimised. The local hormonal effect causes endometrial suppression, leading to reduced menstrual bleeding or amenorrhoea over time.
- Ribavirin is a nucleoside analogue with significant teratogenic and embryocidal effects. It has a prolonged elimination half-life and accumulates in tissues. Both men and women taking ribavirin must use effective contraception during treatment and for at least 6 months after completion due to its persistence in the body. Interferon-alpha is not significantly teratogenic but is generally avoided in pregnancy.
- The standard single-dose regimen for medical management of ectopic pregnancy is methotrexate 50 mg/m² intramuscularly. The dose is calculated based on body surface area. Day 1 treatment is followed by measurement of beta-hCG levels on Days 4 and 7. A second dose may be required if beta-hCG levels do not decline adequately. Methotrexate inhibits dihydrofolate reductase, interfering with DNA synthesis in rapidly dividing trophoblastic tissue.
- Oral ferrous sulphate is the first-line treatment for iron deficiency anaemia in pregnancy due to its efficacy, safety, and low cost. It provides 65 mg of elemental iron per 200 mg tablet. Intravenous iron (e.g., ferric carboxymaltose) is reserved for women who cannot tolerate oral iron, have severe anaemia diagnosed late in pregnancy, or have malabsorption. Parenteral iron carries risks of anaphylaxis.
- Oestrogen in the COCP stimulates hepatic synthesis of various binding globulins, including sex hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG), and thyroid-binding globulin (TBG). It also increases triglycerides and HDL cholesterol and increases coagulation factors, contributing to the thrombotic risk. The progestogen component modifies some of these effects depending on its androgenic activity.
- Gemcitabine is a nucleoside analogue (pyrimidine antimetabolite) commonly associated with flu-like symptoms (fever, myalgia, headache), which can last 1-2 days, and dose-limiting myelosuppression (particularly thrombocytopenia). It also causes a mild rash and peripheral oedema. Pulmonary toxicity is less common than with bleomycin. Docetaxel is associated with peripheral neuropathy and fluid retention.
- The most common insulin regimen for gestational diabetes is a basal-bolus approach, typically NPH (intermediate-acting) insulin twice daily plus short-acting (rapid-acting) insulin before meals. This regimen mimics physiological insulin secretion and provides flexibility for meal timing and content. Rapid-acting analogues (lispro, aspart) are safe in pregnancy and preferred due to better postprandial control and less hypoglycaemia compared to regular insulin.
- Sertraline is a selective serotonin reuptake inhibitor (SSRI) with relatively low levels in breast milk and is considered one of the safest antidepressants during breastfeeding. Its active metabolite, desmethylsertraline, is also present in low concentrations. Paroxetine and fluoxetine have higher breast milk levels. The benefits of treating maternal depression generally outweigh the minimal risks to the nursing infant.
- Carboprost (15-methyl prostaglandin F2α) is a second-line uterotonic agent for postpartum haemorrhage refractory to oxytocin. It causes intense myometrial contractions and is administered intramuscularly (250 μg) or directly into the myometrium. It should be avoided in women with asthma as it can cause bronchospasm. Ergometrine is another option but is contraindicated in hypertension. Tranexamic acid is an adjunctive antifibrinolytic.
- PARP (poly ADP-ribose polymerase) inhibitors such as olaparib, niraparib, and rucaparib inhibit the base excision repair pathway, a key mechanism for repairing single-strand DNA breaks. In tumours with BRCA mutations (which impair homologous recombination repair), PARP inhibition leads to accumulation of double-strand breaks and synthetic lethality. PARP inhibitors are particularly effective in BRCA-mutated ovarian cancers as maintenance therapy.
Mock Exam 10
Mock Exam 10 — Pharmacology
MRCOG Part 1 practice — 100 single best answer questions with answers and explanations.
📘 Q1 (Pharmacology) — A 28-year-old pregnant woman at 32 weeks gestation is prescribed a drug that crosses the placenta primarily by simple diffusion. Which of the following factors most significantly determines the rate of placental transfer of a drug by simple diffusion? A) Molecular weight of the drug B) Lipid solubility of the drug C) Degree of protein binding D) Placental blood flow E) Fetal blood pH
Answer: B
The rate of placental transfer by simple diffusion is most dependent on the lipid solubility of the drug. Lipid-soluble, non-ionized drugs cross the placenta readily, while water-soluble, ionized drugs cross poorly. Molecular weight, protein binding, and blood flow also influence transfer but lipid solubility is the primary determinant for passive diffusion.
📘 Q2 (Pharmacology) — A 35-year-old woman on phenytoin for epilepsy becomes pregnant. She asks about the risk of teratogenicity. Which of the following is the most common congenital abnormality associated with first-trimester exposure to phenytoin? A) Neural tube defects B) Cleft lip and palate C) Congenital heart disease D) Cranial dysostosis E) Limb reduction defects
Answer: B
Fetal hydantoin syndrome, associated with phenytoin use in pregnancy, includes craniofacial abnormalities such as cleft lip and palate, microcephaly, and nail hypoplasia. Neural tube defects are more associated with valproate, while congenital heart disease is linked to lithium. Phenytoin is classified as FDA Category D in pregnancy.
📘 Q3 (Pharmacology) — A 30-year-old woman presents with hyperemesis gravidarum at 10 weeks gestation. Which of the following antiemetics is most appropriate for use in the first trimester of pregnancy? A) Metoclopramide B) Ondansetron C) Doxylamine with pyridoxine D) Prochlorperazine E) Domperidone
Answer: C
Doxylamine with pyridoxine (Vitamin B6) is the first-line antiemetic for nausea and vomiting in early pregnancy, with a well-established safety profile. Ondansetron has been associated with a small increased risk of cleft palate in some studies. Metoclopramide and prochlorperazine are second-line options.
📘 Q4 (Pharmacology) — A 26-year-old woman at 28 weeks gestation presents with preterm labour. Which of the following tocolytic agents acts as an oxytocin receptor antagonist? A) Nifedipine B) Ritodrine C) Atosiban D) Indomethacin E) Magnesium sulphate
Answer: C
Atosiban is a competitive antagonist of oxytocin receptors, inhibiting oxytocin-induced uterine contractions. It is used as a tocolytic agent with fewer cardiovascular side effects compared to beta-agonists like ritodrine. Nifedipine is a calcium channel blocker, indomethacin is a COX inhibitor, and magnesium sulphate acts as a calcium antagonist at the cellular level.
📘 Q5 (Pharmacology) — A pregnant woman at 34 weeks gestation is at risk of preterm delivery within the next 48 hours. Which of the following corticosteroids is most commonly administered to enhance fetal lung maturity? A) Hydrocortisone B) Prednisolone C) Betamethasone D) Dexamethasone E) Triamcinolone
Answer: C
Betamethasone is the preferred corticosteroid for antenatal therapy to accelerate fetal lung maturity, typically given as two doses of 12 mg intramuscularly 24 hours apart. It reduces the incidence of neonatal respiratory distress syndrome, intraventricular haemorrhage, and necrotising enterocolitis. Dexamethasone is an alternative but betamethasone is more widely used in obstetric practice.
📘 Q6 (Pharmacology) — A 32-year-old woman with type 2 diabetes mellitus is planning pregnancy. Her current medications include metformin and glibenclamide. Which of the following is the most appropriate management of her diabetes in the preconception period? A) Continue metformin and glibenclamide B) Switch to insulin C) Continue metformin only D) Switch to glibenclamide only E) Switch to acarbose
Answer: B
Insulin is the gold standard for glycaemic control in pregnancy because it does not cross the placenta significantly and allows precise dose titration. While metformin is increasingly used in gestational diabetes, the preconception period is best managed with insulin to optimise glycaemic control and minimise teratogenic risks. Sulfonylureas like glibenclamide cross the placenta and are not first-line in pregnancy.
📘 Q7 (Pharmacology) — A 45-year-old woman is prescribed tamoxifen as adjuvant therapy for oestrogen receptor-positive breast cancer. Which of the following is the most serious adverse effect associated with long-term tamoxifen use? A) Pulmonary fibrosis B) Venous thromboembolism C) Cardiomyopathy D) Hepatic necrosis E) Renal failure
Answer: B
Tamoxifen, a selective oestrogen receptor modulator (SERM), significantly increases the risk of venous thromboembolism (VTE) including deep vein thrombosis and pulmonary embolism. It also increases the risk of endometrial hyperplasia and carcinoma. Pulmonary fibrosis is associated with bleomycin, and cardiomyopathy is associated with anthracyclines like doxorubicin.
📘 Q8 (Pharmacology) — A 28-year-old woman presents with postpartum haemorrhage due to uterine atony. Which of the following is the first-line medical management? A) Ergometrine B) Carboprost C) Oxytocin D) Misoprostol E) Tranexamic acid
Answer: C
Oxytocin is the first-line agent for the management of postpartum haemorrhage due to uterine atony. It is administered as a slow intravenous infusion and causes sustained rhythmic contractions of the uterus. Ergometrine is a second-line agent but is contraindicated in hypertension. Carboprost (15-methyl prostaglandin F2α) and misoprostol are also used as second-line therapies.
📘 Q9 (Pharmacology) — A 34-year-old woman at 36 weeks gestation is diagnosed with pre-eclampsia. Her blood pressure is 160/105 mmHg. Which of the following antihypertensive agents is most appropriate for acute management? A) Methyldopa B) Labetalol C) Nifedipine D) Hydralazine E) Captopril
Answer: B
Labetalol, a combined alpha- and beta-blocker, is the first-line agent for acute management of severe hypertension in pregnancy due to its rapid onset and favourable safety profile. Nifedipine (short-acting) and hydralazine are alternatives, but labetalol is preferred. Methyldopa is used for chronic hypertension management. ACE inhibitors like captopril are contraindicated in pregnancy due to fetotoxicity.
📘 Q10 (Pharmacology) — A 24-year-old woman with systemic lupus erythematosus requires immunosuppressive therapy during pregnancy. Which of the following immunosuppressants is safest to use in pregnancy? A) Methotrexate B) Mycophenolate mofetil C) Cyclophosphamide D) Azathioprine E) Leflunomide
Answer: D
Azathioprine is considered the safest immunosuppressant among these options in pregnancy, though it crosses the placenta, the fetal liver lacks the enzyme to convert it to its active metabolite. Methotrexate, mycophenolate, cyclophosphamide, and leflunomide are highly teratogenic and contraindicated in pregnancy.
📘 Q11 (Pharmacology) — A 30-year-old woman presents with eclampsia. She is started on magnesium sulphate. Which of the following is the most concerning adverse effect requiring monitoring? A) Hypocalcaemia B) Hypokalaemia C) Respiratory depression D) Hypoglycaemia E) Hepatic impairment
Answer: C
Magnesium sulphate therapy for eclampsia can lead to magnesium toxicity, with respiratory depression being the most serious concern. Deep tendon reflexes are lost at serum magnesium levels around 10 mg/dL, and respiratory depression occurs at higher levels (12-15 mg/dL). Calcium gluconate is the antidote. Monitoring of reflexes, respiratory rate, and urine output is essential.
📘 Q12 (Pharmacology) — A 35-year-old woman with recurrent ovarian cancer is being treated with cisplatin. Which of the following is the dose-limiting toxicity of cisplatin? A) Cardiotoxicity B) Nephrotoxicity C) Hepatotoxicity D) Neurotoxicity E) Ototoxicity
Answer: B
Nephrotoxicity is the dose-limiting toxicity of cisplatin, characterised by acute kidney injury, hypomagnesaemia, and hypokalaemia. Adequate hydration and diuresis are essential protective measures. Ototoxicity (tinnitus and high-frequency hearing loss) is also common, but nephrotoxicity limits the cumulative dose. Cardiotoxicity is associated with doxorubicin.
📘 Q13 (Pharmacology) — A 28-year-old woman on the combined oral contraceptive pill (COCP) develops breakthrough bleeding. Which of the following is the most likely cause? A) Oestrogen dose too high B) Progestogen dose too low C) Oestrogen dose too low D) Progestogen dose too high E) Androgenic effects of the progestogen
Answer: C
Breakthrough bleeding on the COCP is most commonly due to inadequate oestrogen dose, which fails to provide sufficient endometrial stabilisation. Oestrogen promotes endometrial proliferation and stability. Increasing the oestrogen dose or switching to a formulation with a different progestogen can help. If the progestogen dose is too high, it may cause atrophy and also lead to spotting.
📘 Q14 (Pharmacology) — A 22-year-old woman requests emergency contraception 72 hours after unprotected intercourse. Which of the following is the most effective method for emergency contraception at this time point? A) Levonorgestrel 1.5 mg orally B) Ulipristal acetate 30 mg orally C) Copper intrauterine device (Cu-IUD) D) Oestrogen-only pill E) Combined oral contraceptive pill (Yuzpe regimen)
Answer: C
The copper intrauterine device (Cu-IUD) is the most effective method of emergency contraception, effective up to 5 days after unprotected intercourse with a failure rate of less than 1%. Ulipristal acetate (30 mg) is more effective than levonorgestrel and is effective up to 120 hours (5 days) after intercourse. However, the Cu-IUD remains the most effective overall.
📘 Q15 (Pharmacology) — A 38-year-old woman with endometriosis is being treated with a GnRH agonist. Which of the following is the most common adverse effect of this therapy? A) Weight loss B) Vasomotor symptoms (hot flushes) C) Nausea and vomiting D) Acne E) Hirsutism
Answer: B
GnRH agonists (e.g., leuprolide, goserelin) cause an initial flare in gonadotrophin release followed by pituitary downregulation, leading to a hypo-oestrogenic state. The most common adverse effects are vasomotor symptoms (hot flushes), vaginal dryness, and bone mineral density loss. Add-back hormone therapy (oestrogen + progestogen) is often used to mitigate these effects for prolonged treatment.
📘 Q16 (Pharmacology) — A 32-year-old woman at 20 weeks gestation presents with a urinary tract infection. Which of the following antibiotics is most appropriate in pregnancy? A) Ciprofloxacin B) Doxycycline C) Nitrofurantoin D) Gentamicin E) Sulfamethoxazole-trimethoprim
Answer: C
Nitrofurantoin is safe and commonly used for urinary tract infections in pregnancy, particularly in the second trimester. Ciprofloxacin (fluoroquinolone) is avoided due to concerns about arthropathy in the fetus. Doxycycline is contraindicated in pregnancy as tetracyclines cause discolouration of fetal teeth and bone growth impairment. Sulfamethoxazole-trimethoprim should be avoided near term due to the risk of kernicterus.
📘 Q17 (Pharmacology) — A 40-year-old woman with hepatitis B is pregnant. She requires antiviral therapy to reduce the risk of vertical transmission. Which of the following is the most appropriate agent? A) Interferon-alpha B) Ribavirin C) Tenofovir disoproxil fumarate D) Acyclovir E) Oseltamivir
Answer: C
Tenofovir is a nucleotide reverse transcriptase inhibitor used in chronic hepatitis B. It is safe in pregnancy (FDA Category B) and reduces viral load, thereby decreasing the risk of perinatal transmission. Interferon-alpha is not used in pregnancy due to its antiproliferative effects. Ribavirin is teratogenic. Acyclovir is for herpes viruses, not hepatitis B.
📘 Q18 (Pharmacology) — A 29-year-old woman on warfarin for mechanical heart valve is planning pregnancy. Which of the following is the most appropriate anticoagulant management? A) Continue warfarin throughout pregnancy B) Switch to low molecular weight heparin (LMWH) in the first trimester, then warfarin C) Switch to LMWH before conception and continue throughout pregnancy D) Switch to unfractionated heparin (UFH) in the first trimester, then LMWH E) Switch to aspirin monotherapy
Answer: C
Warfarin is teratogenic (FDA Category X), causing fetal warfarin syndrome (nasal hypoplasia, stippled epiphyses) especially between 6-12 weeks gestation. The recommended approach is to switch to LMWH before conception and continue throughout pregnancy, with dose adjustments based on anti-Xa levels. LMWH does not cross the placenta and is safe for the fetus.
📘 Q19 (Pharmacology) — A 34-year-old woman with a body mass index of 38 kg/m² is seeking contraception. Which of the following contraceptive methods has the highest contraceptive efficacy independent of body weight? A) Combined oral contraceptive pill (COCP) B) Progestogen-only pill (POP) C) Copper intrauterine device (Cu-IUD) D) Contraceptive implant (etonogestrel) E) Depot medroxyprogesterone acetate (DMPA)
Answer: C
The copper intrauterine device (Cu-IUD) is a non-hormonal method with efficacy that is not affected by body weight or BMI. Hormonal methods, including the COCP, POP, contraceptive implant, and DMPA, may have reduced efficacy in women with higher BMI due to altered pharmacokinetics. The Cu-IUD provides highly reliable long-term contraception independent of user weight.
📘 Q20 (Pharmacology) — A 36-year-old woman is diagnosed with gestational diabetes at 28 weeks. Fasting blood glucose remains elevated despite dietary modifications. Which of the following oral hypoglycaemic agents is considered safe in pregnancy? A) Metformin B) Glibenclamide C) Rosiglitazone D) Sitagliptin E) Acarbose
Answer: A
Metformin is increasingly used in gestational diabetes and is considered safe in pregnancy (FDA Category B). It does not cause hypoglycaemia and improves insulin sensitivity. While glibenclamide is sometimes used, it crosses the placenta and has been associated with larger birth weight. Rosiglitazone, sitagliptin (DPP-4 inhibitor), and acarbose have limited safety data in pregnancy.
📘 Q21 (Pharmacology) — A 25-year-old woman with epilepsy on lamotrigine becomes pregnant. Which of the following physiological changes in pregnancy most significantly affects lamotrigine levels? A) Increased renal clearance B) Increased hepatic metabolism C) Decreased plasma protein binding D) Increased volume of distribution E) Decreased gastrointestinal absorption
Answer: B
Lamotrigine clearance significantly increases during pregnancy due to increased hepatic glucuronidation, leading to a marked decrease in serum concentrations. This can result in breakthrough seizures if doses are not increased. Monitoring of serum lamotrigine levels and dose adjustment throughout pregnancy and postpartum are essential.
📘 Q22 (Pharmacology) — A 42-year-old woman with relapsed ovarian cancer is being treated with paclitaxel. Which of the following is the most characteristic adverse effect of paclitaxel? A) Haemorrhagic cystitis B) Peripheral neuropathy C) Nephrotoxicity D) Cardiotoxicity E) Pulmonary fibrosis
Answer: B
Paclitaxel, a taxane that stabilises microtubules, commonly causes peripheral sensory neuropathy, which is dose-dependent and cumulative. It is administered with premedication (steroids and antihistamines) to prevent hypersensitivity reactions. Haemorrhagic cystitis is associated with cyclophosphamide, nephrotoxicity with cisplatin, and cardiotoxicity with doxorubicin.
📘 Q23 (Pharmacology) — A 33-year-old breastfeeding woman develops mastitis and requires antibiotic therapy. Which of the following antibiotics is most compatible with breastfeeding? A) Tetracycline B) Ciprofloxacin C) Amoxicillin D) Chloramphenicol E) Clindamycin
Answer: C
Penicillins such as amoxicillin are considered safe during breastfeeding, with minimal excretion into breast milk and no known adverse effects on the infant. Tetracyclines should be avoided as they can cause dental discolouration in the nursing infant. Ciprofloxacin is relatively contraindicated due to concerns about arthropathy, and chloramphenicol carries a risk of grey baby syndrome.
📘 Q24 (Pharmacology) — A 31-year-old woman is receiving carboplatin and paclitaxel for ovarian cancer. Which of the following is the primary mechanism of action of carboplatin? A) Inhibition of topoisomerase II B) Cross-linking of DNA C) Inhibition of microtubule depolymerisation D) Inhibition of dihydrofolate reductase E) Inhibition of thymidylate synthase
Answer: B
Carboplatin, like cisplatin, is a platinum-based alkylating agent that forms intrastrand and interstrand DNA cross-links, thereby inhibiting DNA replication and transcription. Carboplatin is less nephrotoxic and emetogenic than cisplatin but causes more myelosuppression, particularly thrombocytopenia. Topoisomerase II inhibition is the mechanism of etoposide, and microtubule stabilisation is the mechanism of paclitaxel.
📘 Q25 (Pharmacology) — A 26-year-old woman with polycystic ovary syndrome (PCOS) is being treated with clomiphene citrate for ovulation induction. Which of the following best describes the mechanism of action of clomiphene? A) Direct ovarian stimulation B) GnRH agonist activity C) Oestrogen receptor antagonist at the hypothalamus D) Aromatase inhibition E) Progesterone receptor modulation
Answer: C
Clomiphene citrate is a selective oestrogen receptor modulator (SERM) that acts as an antagonist at oestrogen receptors in the hypothalamus, blocking negative feedback and thereby increasing GnRH pulsatility. This leads to increased pituitary FSH and LH secretion, stimulating follicular development. Letrozole (an aromatase inhibitor) has a different mechanism, inhibiting oestrogen synthesis.
📘 Q26 (Pharmacology) — A 28-year-old woman at 30 weeks gestation is diagnosed with pulmonary tuberculosis. Which of the following is the safest first-line anti-tuberculous agent in pregnancy? A) Rifampicin B) Isoniazid C) Ethambutol D) Pyrazinamide E) Streptomycin
Answer: A
Rifampicin is safe in pregnancy and is a cornerstone of anti-tuberculous therapy. Isoniazid is also safe but requires pyridoxine (Vitamin B6) supplementation to prevent peripheral neuropathy. Ethambutol is generally considered safe. Streptomycin, an aminoglycoside, is contraindicated in pregnancy due to the risk of fetal ototoxicity (eighth cranial nerve damage). Pyrazinamide has less safety data but is used when necessary.
📘 Q27 (Pharmacology) — A 34-year-old woman is undergoing in vitro fertilisation (IVF). She is started on a GnRH antagonist protocol. Which of the following is an example of a GnRH antagonist used in assisted reproduction? A) Leuprolide B) Goserelin C) Cetrorelix D) Nafarelin E) Triptorelin
Answer: C
Cetrorelix is a GnRH antagonist used in controlled ovarian hyperstimulation for IVF to prevent premature LH surge. Unlike GnRH agonists (leuprolide, goserelin, nafarelin, triptorelin), antagonists cause immediate suppression of gonadotrophins without an initial flare effect. This allows a shorter treatment cycle and reduced gonadotrophin requirements.
📘 Q28 (Pharmacology) — A 30-year-old woman on methotrexate for ectopic pregnancy develops stomatitis and oral ulceration. Which of the following is the appropriate rescue therapy? A) Vitamin B12 B) Folic acid C) Folinic acid (calcium folinate) D) Iron supplementation E) Vitamin K
Answer: C
Folinic acid (calcium folinate) is the specific antidote for methotrexate toxicity. It bypasses the dihydrofolate reductase blockade caused by methotrexate, providing the reduced folate required for DNA synthesis. Folic acid itself cannot be used as it requires dihydrofolate reductase for conversion to its active form. Folinic acid rescue is standard after high-dose methotrexate therapy.
📘 Q29 (Pharmacology) — A 27-year-old woman with a family history of hereditary thrombophilia is started on the combined oral contraceptive pill. Which of the following progestogens is associated with the lowest risk of venous thromboembolism? A) Desogestrel B) Drospirenone C) Levonorgestrel D) Cyproterone acetate E) Gestodene
Answer: C
Levonorgestrel, a second-generation progestogen, is associated with the lowest risk of venous thromboembolism (VTE) among the common progestogens used in COCPs. Third-generation progestogens (desogestrel, gestodene) and drospirenone carry a slightly higher VTE risk. Cyproterone acetate, used in Dianette, carries a higher VTE risk and is not recommended solely for contraception.
📘 Q30 (Pharmacology) — A 32-year-old woman at 35 weeks gestation is diagnosed with a deep vein thrombosis. She is started on therapeutic low molecular weight heparin (LMWH). Which of the following laboratory tests is most appropriate for monitoring LMWH therapy? A) Activated partial thromboplastin time (aPTT) B) Prothrombin time (PT) C) Anti-factor Xa assay D) Thrombin time (TT) E) International normalised ratio (INR)
Answer: C
Anti-factor Xa assay is the recommended method for monitoring LMWH therapy when monitoring is required (e.g., in pregnancy, extremes of body weight, or renal impairment). LMWH has a predictable dose-response relationship and generally does not require routine monitoring, but pregnancy alters pharmacokinetics, necessitating periodic anti-Xa level monitoring to ensure adequate dosing.
📘 Q31 (Pharmacology) — A 40-year-old woman with breast cancer is receiving doxorubicin chemotherapy. Which of the following is the dose-limiting toxicity of doxorubicin? A) Nephrotoxicity B) Neurotoxicity C) Cardiotoxicity D) Pulmonary fibrosis E) Haemorrhagic cystitis
Answer: C
Doxorubicin, an anthracycline antibiotic, causes cumulative dose-dependent cardiotoxicity characterised by dilated cardiomyopathy and heart failure. The cumulative lifetime dose is typically limited to 450-550 mg/m². Dexrazoxane is a cardioprotectant that can be used. Haemorrhagic cystitis is associated with cyclophosphamide, and pulmonary fibrosis with bleomycin.
📘 Q32 (Pharmacology) — A 24-year-old woman who is 8 weeks pregnant develops hyperthyroidism. Which of the following thyroid medications is most appropriate? A) Radioactive iodine B) Carbimazole C) Propylthiouracil D) Levothyroxine E) Lugol's iodine
Answer: C
Propylthiouracil (PTU) is preferred over carbimazole in the first trimester of pregnancy due to the association of carbimazole with aplasia cutis congenita (scalp defect) in the fetus. PTU is also more highly protein-bound, reducing placental transfer. Radioactive iodine is absolutely contraindicated in pregnancy as it destroys the fetal thyroid gland.
📘 Q33 (Pharmacology) — A 35-year-old woman with endometriosis is being treated with the progesterone-only pill (POP). Which of the following best describes the primary mechanism of action of the POP? A) Suppression of ovulation in all cycles B) Thickening of cervical mucus and endometrial atrophy C) Inhibition of implantation D) Suppression of GnRH release E) Oestrogen receptor antagonism
Answer: B
The primary mechanism of the progesterone-only pill (POP) is thickening of cervical mucus, making it impenetrable to sperm, and induction of endometrial atrophy, which may prevent implantation. Unlike the COCP, the POP does not consistently suppress ovulation in all cycles; about 40-60% of cycles remain ovulatory. Consistent daily intake is critical for effectiveness.
📘 Q34 (Pharmacology) — A 29-year-old woman with uterine fibroids is being treated with ulipristal acetate. Which of the following best describes its mechanism of action? A) GnRH agonist B) GnRH antagonist C) Progesterone receptor modulator D) Aromatase inhibitor E) Dopamine agonist
Answer: C
Ulipristal acetate is a selective progesterone receptor modulator (SPRM) that exerts tissue-specific agonist, antagonist, or mixed effects on progesterone receptors. It reduces fibroid size by inhibiting cell proliferation and inducing apoptosis. It is also used for emergency contraception. GnRH agonists (e.g., leuprolide) and antagonists (e.g., cetrorelix) work via different mechanisms.
📘 Q35 (Pharmacology) — A 33-year-old woman with severe ovarian hyperstimulation syndrome (OHSS) develops oliguria and haemoconcentration. Which of the following is the most appropriate pharmacological intervention? A) Intravenous furosemide B) Intravenous albumin with volume expansion C) Oral spironolactone D) Intravenous dopamine E) Oral metformin
Answer: B
The management of severe OHSS involves volume expansion with intravenous fluids and human albumin to maintain intravascular volume and improve renal perfusion. Diuretics like furosemide are contraindicated as they worsen haemoconcentration and hypovolaemia. Dopamine at low doses has been used but albumin with crystalloids is the mainstay. The underlying pathophysiology is increased capillary permeability.
📘 Q36 (Pharmacology) — A 38-year-old woman is diagnosed with bacterial vaginosis in pregnancy. Which of the following antibiotics is most appropriate for treatment? A) Metronidazole oral B) Metronidazole vaginal gel C) Clindamycin oral D) Clindamycin vaginal cream E) Doxycycline
Answer: A
Oral metronidazole is the recommended treatment for bacterial vaginosis in pregnancy to reduce the risk of preterm birth, particularly in high-risk women. Although topical preparations are effective for symptomatic relief, oral therapy achieves better tissue penetration and is preferred in pregnancy. Doxycycline is contraindicated in pregnancy and tetracyclines are avoided.
📘 Q37 (Pharmacology) — A 26-year-old woman with a history of venous thromboembolism is seeking contraception. Which of the following contraceptive methods is contraindicated? A) Progestogen-only pill B) Copper intrauterine device C) Combined oral contraceptive pill D) Contraceptive implant E) Levonorgestrel-releasing intrauterine system (LNG-IUS)
Answer: C
The combined oral contraceptive pill (COCP) is contraindicated in women with a history of venous thromboembolism (VTE) due to the oestrogen component, which increases the risk of thrombotic events. Progestogen-only methods (POP, implant, LNG-IUS) and the copper IUD are safe alternatives as they do not increase VTE risk.
📘 Q38 (Pharmacology) — A 31-year-old woman at 14 weeks gestation experiences an asthma exacerbation. Which of the following is the most appropriate acute management? A) Oral prednisolone B) Inhaled salbutamol C) Inhaled beclomethasone D) Intravenous aminophylline E) Oral theophylline
Answer: B
Inhaled short-acting beta-agonists like salbutamol are the first-line acute treatment for asthma exacerbation in pregnancy, as in non-pregnant patients. Inhaled route delivers the drug directly to the airways with minimal systemic absorption, making it safe in pregnancy. Systemic corticosteroids may be added for severe exacerbations but inhaled beta-agonists are the priority.
📘 Q39 (Pharmacology) — A 22-year-old woman requests the contraceptive injection (depot medroxyprogesterone acetate, DMPA). Which of the following is a concern with long-term use of DMPA? A) Increased risk of VTE B) Decreased bone mineral density C) Increased risk of breast cancer D) Ovarian failure E) Endometrial hyperplasia
Answer: B
Long-term use of DMPA is associated with decreased bone mineral density due to suppression of oestradiol levels. The bone loss is partially reversible after discontinuation. DMPA is an effective contraceptive with the convenience of once-every-13-week administration. It does not increase VTE risk (unlike COCP) and does not cause ovarian failure or endometrial hyperplasia.
📘 Q40 (Pharmacology) — A 45-year-old woman with endometrial cancer is being treated with megestrol acetate. Which of the following best describes the mechanism of action of megestrol acetate? A) GnRH agonist B) Aromatase inhibitor C) Progestogen D) Anti-oestrogen E) Cytotoxic chemotherapy
Answer: C
Megestrol acetate is a synthetic progestogen used in the treatment of advanced or recurrent endometrial cancer. It acts by opposing the proliferative effects of oestrogen on the endometrium, inducing secretory transformation and eventually atrophy. Progestogens are effective in hormone-sensitive endometrial cancers, particularly those that are well-differentiated and oestrogen receptor-positive.
📘 Q41 (Pharmacology) — A 36-year-old woman with group B streptococcus (GBS) colonisation in pregnancy is in labour. Which antibiotic is most appropriate for intrapartum prophylaxis? A) Oral amoxicillin B) Intravenous gentamicin C) Intravenous benzylpenicillin D) Oral cefalexin E) Intravenous clindamycin
Answer: C
Intravenous benzylpenicillin (Penicillin G) is the preferred agent for intrapartum GBS prophylaxis, with a loading dose followed by maintenance doses every 4 hours until delivery. Intravenous administration ensures adequate fetal serum levels. Clindamycin is reserved for women with severe penicillin allergy. Oral antibiotics are inadequate for intrapartum prophylaxis due to unpredictable absorption.
📘 Q42 (Pharmacology) — A 27-year-old woman who is breastfeeding develops a fungal infection. Which of the following antifungal agents is safest during lactation? A) Fluconazole B) Ketoconazole C) Itraconazole D) Griseofulvin E) Amphotericin B
Answer: A
Fluconazole is excreted into breast milk in low concentrations and is considered compatible with breastfeeding. It is commonly used for vaginal candidiasis during lactation. Ketoconazole and itraconazole have limited data but are generally avoided. Griseofulvin is contraindicated as it has been associated with hepatotoxicity in nursing infants. Amphotericin B is poorly absorbed orally.
📘 Q43 (Pharmacology) — A 30-year-old woman at 12 weeks gestation is prescribed codeine for pain relief. Which of the following is the primary reason codeine is not preferred in pregnancy? A) High risk of teratogenicity B) Variable metabolism by CYP2D6 leading to unpredictable neonatal effects C) Increased risk of spontaneous abortion D) High placental transfer causing fetal addiction E) Inadequate pain relief in pregnancy
Answer: B
Codeine is a prodrug that is metabolised by CYP2D6 into morphine. Genetic variability in CYP2D6 activity (ultra-rapid metabolisers) can lead to high levels of morphine, posing a risk of neonatal respiratory depression and opioid withdrawal. Paracetamol and low-dose ibuprofen (avoid in third trimester) are preferred for pain relief in pregnancy.
📘 Q44 (Pharmacology) — A 34-year-old woman is undergoing chemotherapy for ovarian cancer with a regimen that causes severe nausea. Which of the following antiemetics acts by blocking the NK1 receptor? A) Ondansetron B) Metoclopramide C) Aprepitant D) Haloperidol E) Dexamethasone
Answer: C
Aprepitant is a neurokinin-1 (NK1) receptor antagonist that blocks substance P, a key neurotransmitter in the emetic pathway. It is used in combination with a 5-HT3 antagonist (ondansetron) and dexamethasone for highly emetogenic chemotherapy regimens, such as those containing cisplatin. Ondansetron is a 5-HT3 antagonist, and metoclopramide is a dopamine D2 antagonist.
📘 Q45 (Pharmacology) — A 28-year-old woman with epilepsy is taking valproate and is planning pregnancy. Which of the following is the most important counselling point regarding valproate in pregnancy? A) Low risk of major malformations B) Dose-dependent risk of neural tube defects and neurodevelopmental delay C) Safe alternative to other antiepileptic drugs in pregnancy D) Risk limited to the first trimester only E) No increased risk compared to the general population
Answer: B
Valproate carries the highest risk of major congenital malformations (especially neural tube defects) among antiepileptic drugs, with a dose-dependent relationship. Additionally, it is associated with neurodevelopmental delay and reduced IQ in children exposed in utero. It should be avoided in pregnancy when possible, and women of childbearing potential should use effective contraception.
📘 Q46 (Pharmacology) — A 39-year-old woman is prescribed raloxifene for osteoporosis. Which of the following describes the mechanism of action of raloxifene? A) Oestrogen agonist at bone, antagonist at breast and endometrium B) Pure oestrogen antagonist C) Bisphosphonate action D) Calcium receptor agonist E) Vitamin D analogue
Answer: A
Raloxifene is a second-generation selective oestrogen receptor modulator (SERM) with oestrogen-agonist effects on bone (increasing bone mineral density) and oestrogen-antagonist effects on breast and endometrial tissue. Unlike tamoxifen, which stimulates the endometrium, raloxifene does not increase endometrial cancer risk. It reduces the risk of vertebral fractures in postmenopausal osteoporosis.
📘 Q47 (Pharmacology) — A 32-year-old woman at 32 weeks gestation with chronic hypertension is well-controlled on methyldopa. Which of the following best describes the mechanism of action of methyldopa? A) Beta-blocker B) Alpha-2 adrenergic agonist in the CNS C) Calcium channel blocker D) Direct vasodilator E) ACE inhibitor
Answer: B
Methyldopa is metabolised to alpha-methylnorepinephrine, which acts as an agonist at central alpha-2 adrenergic receptors in the brainstem, reducing sympathetic outflow and decreasing peripheral vascular resistance. It is the preferred first-line antihypertensive for chronic hypertension in pregnancy due to its extensive safety record. It does not significantly reduce uteroplacental blood flow.
📘 Q48 (Pharmacology) — A 25-year-old woman is started on the etonogestrel contraceptive implant (Nexplanon). Which of the following adverse effects is most likely to lead to discontinuation? A) Weight gain B) Acne C) Irregular menstrual bleeding D) Headache E) Mood changes
Answer: C
Irregular menstrual bleeding, including prolonged spotting, oligomenorrhoea, or amenorrhoea, is the most common adverse effect leading to discontinuation of the etonogestrel implant. This unpredictable bleeding pattern occurs due to the progestin-induced endometrial suppression and atrophy. The pattern stabilises over time but can be bothersome enough for women to request removal.
📘 Q49 (Pharmacology) — A 41-year-old woman with cervical cancer is receiving cisplatin chemotherapy. Pre-treatment hydration is essential. Which of the following best explains the rationale for aggressive hydration? A) To prevent cardiotoxicity B) To prevent nephrotoxicity C) To prevent neurotoxicity D) To prevent myelosuppression E) To prevent ototoxicity
Answer: B
Aggressive intravenous hydration before and after cisplatin administration is essential to prevent nephrotoxicity, which is the dose-limiting toxicity of cisplatin. Hydration with normal saline and maintenance of high urine output helps reduce the concentration of cisplatin in the renal tubules, thereby minimising tubular damage. Mannitol may also be added to promote diuresis.
📘 Q50 (Pharmacology) — A 28-year-old woman with severe hyperemesis gravidarum is unable to tolerate oral medications. Which of the following antiemetics can be administered intravenously in pregnancy? A) Doxylamine B) Pyridoxine C) Metoclopramide D) Cyclizine E) Prochlorperazine
Answer: C
Metoclopramide can be administered intravenously and is commonly used in the hospital management of hyperemesis gravidarum. It is a dopamine D2 receptor antagonist with prokinetic properties. While doxylamine and pyridoxine are first-line, they are only available in oral formulations. Cyclizine and prochlorperazine are options but metoclopramide is preferred for IV use.
📘 Q51 (Pharmacology) — A 35-year-old woman with a copper intrauterine device (Cu-IUD) in situ presents with heavy menstrual bleeding. Which of the following best explains the mechanism by which the Cu-IUD causes increased menstrual bleeding? A) Hormonal endometrial suppression B) Local inflammatory reaction and altered endometrial vascularity C) Systemic anticoagulant effect D) Increased prostaglandin synthesis E) Uterine fibroid formation
Answer: B
The copper intrauterine device causes a sterile local inflammatory reaction in the endometrium, characterised by infiltration of leukocytes and prostaglandin release. This inflammatory response alters endometrial vascularity and can lead to increased menstrual blood loss and dysmenorrhoea. The levonorgestrel-releasing IUS (Mirena) has the opposite effect, reducing menstrual bleeding.
📘 Q52 (Pharmacology) — A 33-year-old woman with chronic kidney disease (eGFR 25 mL/min) develops a urinary tract infection in pregnancy. Which antibiotic requires dose adjustment for renal impairment? A) Amoxicillin B) Nitrofurantoin C) Cefalexin D) Gentamicin E) Erythromycin
Answer: D
Gentamicin, an aminoglycoside, is primarily excreted unchanged by the kidneys and requires dose adjustment in renal impairment to avoid ototoxicity and nephrotoxicity. Therapeutic drug monitoring is recommended. Nitrofurantoin is contraindicated if eGFR is less than 30 mL/min due to accumulation and risk of peripheral neuropathy. Amoxicillin and cefalexin require adjustment only in severe impairment.
📘 Q53 (Pharmacology) — A 29-year-old woman with a history of recurrent miscarriages is found to have antiphospholipid syndrome (APS). Which of the following is the standard pharmacological management in pregnancy? A) Aspirin monotherapy B) Low molecular weight heparin (LMWH) plus low-dose aspirin C) Warfarin D) Prednisolone E) Intravenous immunoglobulin
Answer: B
The standard treatment for antiphospholipid syndrome in pregnancy is a combination of low molecular weight heparin (LMWH) and low-dose aspirin (75 mg daily). This regimen significantly improves pregnancy outcomes, including live birth rates, by preventing thrombotic events at the placental level. Warfarin is teratogenic and avoided. Prednisolone and IVIG are reserved for refractory cases.
📘 Q54 (Pharmacology) — A 37-year-old woman with epilepsy on carbamazepine becomes pregnant. Which of the following vitamins should be supplemented at a higher dose due to carbamazepine-induced depletion? A) Vitamin A B) Vitamin C C) Vitamin D D) Folic acid E) Vitamin B12
Answer: D
Carbamazepine is an enzyme-inducing antiepileptic drug that accelerates folate metabolism, increasing the risk of folate deficiency and neural tube defects. Women on carbamazepine (and valproate) should receive high-dose folic acid (5 mg daily) preconception and in the first trimester. Vitamin D may also be affected but the most critical supplementation is folic acid.
📘 Q55 (Pharmacology) — A 24-year-old woman with no medical problems requests the combined oral contraceptive pill. Which of the following is an absolute contraindication to COCP use? A) Body mass index of 30 kg/m² B) Smoker aged 35 years C) Migraine without aura D) Family history of breast cancer E) Varicose veins
Answer: B
Smoking in women aged 35 years or older is an absolute contraindication (UKMEC 4) to COCP use due to the significantly increased risk of cardiovascular events, including myocardial infarction and stroke. BMI of 30 kg/m² (UKMEC 2) and migraine without aura (UKMEC 2) are relative contraindications. Family history of breast cancer and varicose veins are not contraindications.
📘 Q56 (Pharmacology) — A 40-year-old woman with recurrent ovarian cancer is being treated with liposomal doxorubicin. What is the advantage of the liposomal formulation compared to conventional doxorubicin? A) Reduced cardiotoxicity B) Increased oral bioavailability C) Reduced myelosuppression D) Enhanced renal clearance E) Reduced alopecia
Answer: A
Pegylated liposomal doxorubicin has a favourable toxicity profile with reduced cardiotoxicity compared to conventional doxorubicin. The liposomal encapsulation alters the pharmacokinetics, prolonging circulation time and allowing preferential accumulation in tumour tissue. While hand-foot syndrome (palmar-plantar erythrodysesthesia) is more common, cardiac risk is significantly reduced, allowing higher cumulative doses.
📘 Q57 (Pharmacology) — A 26-year-old woman at 24 weeks gestation is diagnosed with syphilis. Which of the following is the most appropriate treatment? A) Oral doxycycline B) Intramuscular ceftriaxone C) Intramuscular benzathine penicillin G D) Oral azithromycin E) Intravenous vancomycin
Answer: C
Intramuscular benzathine penicillin G is the treatment of choice for syphilis in pregnancy, as it effectively treats the mother and prevents congenital syphilis in the fetus. Doxycycline is contraindicated in pregnancy. Ceftriaxone and azithromycin are alternatives but penicillin remains first-line. Intravenous penicillin G is used for neurosyphilis.
📘 Q58 (Pharmacology) — A 34-year-old woman with endometriosis is being treated with danazol. Which of the following adverse effects is most characteristic of danazol therapy? A) Hot flushes B) Androgenic effects (hirsutism, voice deepening) C) Osteoporosis D) Venous thromboembolism E) Endometrial hyperplasia
Answer: B
Danazol is a synthetic androgen derivative that suppresses gonadotrophins and creates a hypo-oestrogenic environment. Its use is limited by androgenic side effects including hirsutism, deepening of the voice, acne, and weight gain. These side effects can be irreversible, particularly voice changes, which limits its long-term use. GnRH agonists have largely replaced danazol in clinical practice.
📘 Q59 (Pharmacology) — A 31-year-old woman with a strong family history of ovarian cancer is considering risk-reducing strategies. Which of the following medications has been shown to reduce the risk of ovarian cancer? A) Tamoxifen B) Combined oral contraceptive pill C) Letrozole D) Clomiphene citrate E) GnRH agonists
Answer: B
The combined oral contraceptive pill (COCP) has been consistently shown to reduce the risk of ovarian cancer by approximately 40-50% with long-term use, and the protective effect persists for decades after discontinuation. The mechanism is thought to be suppression of ovulation, reducing epithelial trauma and inflammation. Tamoxifen reduces breast cancer risk but not ovarian cancer.
📘 Q60 (Pharmacology) — A 28-year-old woman at 38 weeks gestation develops acute pyelonephritis. She has a penicillin allergy (anaphylaxis). Which of the following antibiotics is most appropriate? A) Ceftriaxone B) Ciprofloxacin C) Gentamicin D) Aztreonam E) Nitrofurantoin
Answer: D
Aztreonam is a monobactam antibiotic with activity against gram-negative bacteria and minimal cross-reactivity with penicillins, making it a safe option in true penicillin allergy. Ceftriaxone (cephalosporin) has some cross-reactivity risk. Ciprofloxacin is relatively contraindicated in pregnancy. Gentamicin may be used but requires monitoring. Nitrofurantoin does not achieve adequate renal tissue levels for pyelonephritis.
📘 Q61 (Pharmacology) — A 33-year-old woman is undergoing controlled ovarian hyperstimulation for IVF. She is at high risk of developing ovarian hyperstimulation syndrome (OHSS). Which of the following pharmacological agents is used as a trigger for final oocyte maturation to reduce the risk of OHSS? A) Human chorionic gonadotrophin (hCG) B) GnRH agonist C) GnRH antagonist D) Clomiphene citrate E) Recombinant FSH
Answer: B
In women at high risk of OHSS, a GnRH agonist (e.g., buserelin, triptorelin) is used as the trigger for final oocyte maturation instead of hCG. The GnRH agonist causes an endogenous LH surge from the pituitary, which is shorter in duration and reduces the risk of OHSS compared to exogenous hCG. This is only possible in GnRH antagonist protocols.
📘 Q62 (Pharmacology) — A 36-year-old woman with a history of postpartum psychosis is started on lithium postpartum. Which of the following is the most important monitoring parameter for lithium therapy? A) Full blood count B) Liver function tests C) Serum lithium levels D) Thyroid function tests E) Renal function tests
Answer: C
Lithium has a narrow therapeutic index (0.6-1.2 mmol/L) and toxicity occurs at levels above 1.5 mmol/L. Regular monitoring of serum lithium levels is essential, along with renal and thyroid function tests. However, serum drug level monitoring is the most critical for dose adjustment and preventing toxicity. Signs of toxicity include tremor, ataxia, confusion, and seizures.
📘 Q63 (Pharmacology) — A 27-year-old woman at 16 weeks gestation is diagnosed with an episode of genital herpes. Which of the following antiviral agents is most appropriate? A) Acyclovir B) Valacyclovir C) Famciclovir D) Ganciclovir E) Foscarnet
Answer: A
Acyclovir is the most studied antiviral for herpes simplex virus in pregnancy and has a well-established safety profile. It is used for primary or recurrent genital herpes to reduce the duration and severity of symptoms and to suppress viral shedding. Valacyclovir is also safe but acyclovir has the most safety data. Ganciclovir and foscarnet are reserved for life-threatening CMV and are not used in pregnancy.
📘 Q64 (Pharmacology) — A 30-year-old woman with menorrhagia is being treated with tranexamic acid. Which of the following best describes the mechanism of action of tranexamic acid? A) Vitamin K-dependent clotting factor synthesis B) Inhibition of plasminogen activation C) Platelet aggregation enhancement D) Thrombin activation E) Antithrombin III activation
Answer: B
Tranexamic acid is an antifibrinolytic agent that competitively inhibits the activation of plasminogen to plasmin, thereby preventing fibrin clot breakdown. It reduces menstrual blood loss by approximately 40-50% in women with menorrhagia. It is also used in trauma and postpartum haemorrhage. It does not affect clotting factor synthesis or platelet function.
📘 Q65 (Pharmacology) — A 42-year-old woman with advanced cervical cancer is receiving palliative chemotherapy. She develops febrile neutropenia. Which of the following is the most appropriate immediate management? A) Oral antibiotics and outpatient follow-up B) Intravenous broad-spectrum antibiotics and hospitalisation C) Granulocyte colony-stimulating factor (G-CSF) alone D) Reduction of chemotherapy dose E) Blood transfusion
Answer: B
Febrile neutropenia is an oncological emergency requiring immediate hospitalisation and intravenous broad-spectrum antibiotics after appropriate cultures. The most common pathogens are gram-negative bacilli. G-CSF may be used as adjunctive therapy or prophylaxis in subsequent cycles but does not replace the need for urgent antibiotics. Dose reduction may be considered for future cycles.
📘 Q66 (Pharmacology) — A 25-year-old woman at 20 weeks gestation presents with an acute asthmatic attack requiring systemic corticosteroids. Which corticosteroid is preferred in pregnancy? A) Dexamethasone B) Betamethasone C) Prednisolone D) Fludrocortisone E) Triamcinolone
Answer: C
Prednisolone is the preferred systemic corticosteroid in pregnancy because it is extensively metabolised to inactive forms by placental 11-beta-hydroxysteroid dehydrogenase type 2, limiting fetal exposure. Dexamethasone and betamethasone are less effectively metabolised by the placenta and result in higher fetal concentrations. They are specifically used for fetal lung maturation when indicated.
📘 Q67 (Pharmacology) — A 34-year-old woman with breast cancer is receiving trastuzumab. Which of the following best describes the mechanism of action of trastuzumab? A) Monoclonal antibody against VEGF B) Monoclonal antibody against HER2/neu receptor C) Tyrosine kinase inhibitor D) Microtubule stabiliser E) Aromatase inhibitor
Answer: B
Trastuzumab (Herceptin) is a humanised monoclonal antibody that targets the HER2/neu (ErbB2) receptor, which is overexpressed in approximately 20% of breast cancers. It inhibits downstream signalling pathways, leading to cell cycle arrest and antibody-dependent cellular cytotoxicity. It is associated with cardiotoxicity, particularly when combined with anthracyclines. Bevacizumab targets VEGF.
📘 Q68 (Pharmacology) — A 29-year-old woman with Crohn's disease is well-controlled on infliximab and is planning pregnancy. Which of the following statements regarding infliximab in pregnancy is correct? A) Infliximab is contraindicated in pregnancy B) Infliximab crosses the placenta minimally in the first trimester C) Infliximab should be stopped 6 months before conception D) Infliximab levels in the infant decline rapidly after birth E) Infliximab is a small molecule that freely crosses the placenta
Answer: B
Infliximab, a monoclonal antibody (IgG1), crosses the placenta minimally in the first trimester but increasingly after 20 weeks gestation due to active transport via FcRn receptors. It is generally considered safe to continue in pregnancy for women with moderate-to-severe Crohn's disease. Infants exposed in utero may have detectable drug levels for several months, and live vaccines should be avoided for the first 6 months of life.
📘 Q69 (Pharmacology) — A 38-year-old woman with endometrial hyperplasia without atypia is being treated with a levonorgestrel-releasing intrauterine system (LNG-IUS). Which of the following best describes its local effect on the endometrium? A) Endometrial proliferation B) Endometrial atrophy and decidualisation C) Endometrial necrosis D) Increased endometrial angiogenesis E) Endometrial fibrosis
Answer: B
The LNG-IUS releases levonorgestrel locally into the endometrial cavity, causing profound endometrial suppression with glandular atrophy and stromal decidualisation. This leads to a thin, inactive endometrium, which is the mechanism for treating endometrial hyperplasia and reducing menstrual bleeding. The systemic hormone levels are low, minimising systemic progestogenic side effects.
📘 Q70 (Pharmacology) — A 32-year-old woman is prescribed cabergoline for hyperprolactinaemia-induced infertility. Which of the following is the mechanism of action of cabergoline? A) Dopamine receptor antagonist B) Dopamine D2 receptor agonist C) Serotonin receptor antagonist D) Prolactin receptor antagonist E) Oestrogen receptor modulator
Answer: B
Cabergoline is a long-acting dopamine D2 receptor agonist that suppresses prolactin secretion by the anterior pituitary lactotroph cells. By binding to dopamine receptors on lactotrophs, it inhibits prolactin synthesis and release, restoring ovulatory cycles and fertility. It is more effective and better tolerated than bromocriptine, with fewer gastrointestinal side effects and once- or twice-weekly dosing.
📘 Q71 (Pharmacology) — A 26-year-old woman at 10 weeks gestation is diagnosed with hypothyroidism (TSH 12 mIU/L, low free T4). Which of the following is the most appropriate management? A) Start propylthiouracil B) Start carbimazole C) Start levothyroxine D) Start liothyronine E) Observe and repeat thyroid function in 4 weeks
Answer: C
Levothyroxine (T4) replacement is the standard treatment for hypothyroidism in pregnancy. Maintaining euthyroid status is critical for fetal neurodevelopment, particularly in the first trimester when the fetus is entirely dependent on maternal thyroid hormone. Women with hypothyroidism typically require a 30-50% dose increase in pregnancy due to increased volume of distribution and placental transfer of T4.
📘 Q72 (Pharmacology) — A 35-year-old woman with recurrent vulvovaginal candidiasis is prescribed fluconazole. She is trying to conceive. Which of the following is the most important counselling point? A) Fluconazole is safe at any dose in pregnancy B) High-dose fluconazole in the first trimester is associated with an increased risk of fetal abnormalities C) Fluconazole causes infertility D) Fluconazole should be avoided for life in women of childbearing age E) Fluconazole is only available as an intravenous formulation
Answer: B
Epidemiological studies have shown that high-dose fluconazole (400-800 mg daily) in the first trimester may be associated with an increased risk of fetal abnormalities, including craniosynostosis and cardiac defects. However, single low-dose fluconazole (150 mg) for vaginal candidiasis is generally considered low risk. Women trying to conceive should be counselled appropriately, and single-dose therapy is acceptable if indicated.
📘 Q73 (Pharmacology) — A 40-year-old woman is undergoing chemotherapy for advanced ovarian cancer with carboplatin. Her serum creatinine is elevated. Which of the following best describes how carboplatin dosing is calculated? A) Based on body surface area (mg/m²) B) Based on the Calvert formula using glomerular filtration rate C) Fixed dose for all patients D) Based on body weight (mg/kg) E) Based on age and gender
Answer: B
Carboplatin dosing is calculated using the Calvert formula: Dose (mg) = target AUC × (GFR + 25). Unlike cisplatin, carboplatin is primarily excreted renally, and its dose must be adjusted for renal function to avoid excessive myelosuppression (particularly thrombocytopenia). The target AUC is typically 5-7.5 depending on the treatment protocol. Body surface area-based dosing is used for most other chemotherapeutic agents.
📘 Q74 (Pharmacology) — A 23-year-old woman with menorrhagia is prescribed the combined oral contraceptive pill. How does the COCP reduce menstrual blood loss? A) By increasing endometrial prostaglandins B) By promoting endometrial proliferation C) By suppressing endometrial growth through stabilisation D) By increasing platelet aggregation E) By inducing uterine vasoconstriction
Answer: C
The COCP reduces menstrual blood loss by providing a stable hormonal environment that suppresses endometrial proliferation. The oestrogen component stabilises the endometrium, while the progestogen component causes a thin, atrophic endometrium. This results in lighter, more predictable withdrawal bleeds. The reduction in menstrual blood loss is approximately 40-50% in women with menorrhagia.
📘 Q75 (Pharmacology) — A 34-year-old woman with preterm premature rupture of membranes (PPROM) at 30 weeks is started on erythromycin. What is the primary purpose of antibiotic therapy in PPROM? A) Treatment of chorioamnionitis B) Prophylaxis against group B streptococcus C) Prolongation of pregnancy and reduction of neonatal morbidity D) Prevention of maternal sepsis E) Treatment of urinary tract infection
Answer: C
Erythromycin (a macrolide antibiotic) is used in PPROM to prolong pregnancy and reduce neonatal morbidity, particularly the incidence of neonatal infection, intraventricular haemorrhage, and necrotising enterocolitis. The ORACLE trial demonstrated benefits of erythromycin in PPROM. Co-amoxiclav is avoided due to an increased risk of neonatal necrotising enterocolitis.
📘 Q76 (Pharmacology) — A 28-year-old woman is diagnosed with a hydatidiform mole and requires evacuation. Which of the following medications is used as an alternative to oxytocin for uterine evacuation? A) Ergometrine B) Carboprost C) Misoprostol D) Dinoprostone E) Mifepristone
Answer: C
Misoprostol (a prostaglandin E1 analogue) can be used as an alternative or adjunct to oxytocin for cervical ripening and uterine evacuation in molar pregnancy. It is particularly useful when oxytocin is ineffective. However, caution is needed as prostaglandins may increase the risk of trophoblastic embolisation in complete molar pregnancies. Surgical evacuation remains the primary treatment.
📘 Q77 (Pharmacology) — A 37-year-old woman with BRCA1 mutation undergoes risk-reducing salpingo-oophorectomy. Postoperatively, she develops menopausal symptoms. Which of the following is the most appropriate hormone replacement therapy? A) Oestrogen-only therapy B) Combined oestrogen-progestogen therapy C) Tibolone D) Progestogen-only therapy E) No hormone therapy is safe
Answer: A
Oestrogen-only hormone replacement therapy is appropriate for women who have undergone hysterectomy and bilateral salpingo-oophorectomy, as there is no risk of endometrial cancer. Combined therapy is required only for women with an intact uterus to prevent endometrial hyperplasia. Tibolone is a synthetic steroid with oestrogenic, progestogenic, and androgenic activities but is not first-line.
📘 Q78 (Pharmacology) — A 31-year-old woman presents with an incomplete miscarriage at 12 weeks gestation. Which of the following medications can be used for medical management? A) Oxytocin B) Misoprostol C) Carboprost D) Ergometrine E) Mifepristone
Answer: B
Misoprostol (prostaglandin E1 analogue) is the standard medication for medical management of incomplete miscarriage and first-trimester termination of pregnancy. It causes cervical ripening and uterine contractions, leading to expulsion of products of conception. Oxytocin is less effective in the first trimester due to lower oxytocin receptor density. Mifepristone (an antiprogestogen) can be used in combination with misoprostol for medical abortion.
📘 Q79 (Pharmacology) — A 29-year-old woman with a history of depression is started on the COCP. After 3 months, she reports significant mood changes. Which of the following is the most appropriate management? A) Continue the same pill as mood changes are not related to COCP B) Switch to a pill with a different progestogen C) Add an antidepressant D) Discontinue hormonal contraception and use barrier methods E) Increase the oestrogen dose
Answer: B
Mood changes are a recognised side effect of the COCP, particularly related to the progestogen component. Switching to a formulation with a different progestogen, such as one with a lower androgenic profile (e.g., drospirenone with its anti-mineralocorticoid properties), may improve mood symptoms. If symptoms persist, alternative non-hormonal contraception should be considered.
📘 Q80 (Pharmacology) — A 42-year-old woman with vulval cancer is prescribed topical imiquimod. Which of the following best describes the mechanism of action of imiquimod? A) Direct antiviral effect B) Immune response modifier via Toll-like receptor 7 agonism C) Cytotoxic chemotherapy D) Anti-angiogenic agent E) Hormonal therapy
Answer: B
Imiquimod is an immune response modifier that acts as a Toll-like receptor 7 (TLR7) agonist, stimulating the innate immune system. It induces production of interferon-alpha, tumour necrosis factor-alpha, and other cytokines, thereby enhancing the local immune response against viral infections and neoplastic cells. It is used topically for vulval warts, vulval intraepithelial neoplasia (VIN), and superficial basal cell carcinoma.
📘 Q81 (Pharmacology) — A 33-year-old woman at 36 weeks gestation is in the latent phase of labour and requests analgesia. Which of the following opioid analgesics has the shortest half-life and is most suitable for use in labour? A) Morphine B) Pethidine (meperidine) C) Fentanyl D) Codeine E) Nalbuphine
Answer: C
Fentanyl is a synthetic opioid with a rapid onset and short duration of action (half-life approximately 2-4 hours), making it suitable for labour analgesia with minimal neonatal respiratory depression if carefully timed. Pethidine has a longer half-life and its metabolite, norpethidine, can accumulate in the neonate, causing prolonged respiratory depression. Morphine also has a longer duration of action.
📘 Q82 (Pharmacology) — A 27-year-old woman with PCOS is started on letrozole for ovulation induction. Which of the following best describes the mechanism of action of letrozole? A) Oestrogen receptor antagonist B) Aromatase inhibitor C) GnRH agonist D) Anti-androgen E) Progesterone receptor modulator
Answer: B
Letrozole is a third-generation aromatase inhibitor that reversibly inhibits the aromatase enzyme, blocking the conversion of androgens to oestrogens in peripheral tissues. The reduction in oestrogen levels reduces negative feedback on the hypothalamus and pituitary, leading to increased FSH secretion and follicular development. It has largely replaced clomiphene citrate as first-line ovulation induction due to better pregnancy rates and lower risk of multiple pregnancy.
📘 Q83 (Pharmacology) — A 36-year-old woman with a history of recurrent miscarriage and antiphospholipid syndrome is on LMWH and aspirin. At what point should LMWH be discontinued prior to induction of labour? A) 48 hours before induction B) 24 hours before induction C) 12 hours before induction D) 6 hours before induction E) At the time of membrane rupture
Answer: B
Therapeutic LMWH should be discontinued approximately 24 hours before planned induction of labour or caesarean section to allow clearance of the anticoagulant effect and reduce the risk of bleeding complications. Regional anaesthesia (neuraxial blockade) should not be administered within 24 hours of the last therapeutic dose of LMWH. Prophylactic LMWH may be stopped 12 hours prior.
📘 Q84 (Pharmacology) — A 30-year-old woman at 22 weeks gestation presents with acute gout. Which of the following is the most appropriate treatment for acute gout in pregnancy? A) Colchicine B) Indomethacin C) Prednisolone D) Allopurinol E) Febuxostat
Answer: C
Prednisolone (oral corticosteroid) is the preferred treatment for acute gout in pregnancy, as it is safe and effective. NSAIDs like indomethacin should be avoided, particularly in the third trimester, due to the risk of premature closure of the ductus arteriosus and oligohydramnios. Colchicine has limited safety data. Allopurinol and febuxostat are urate-lowering therapies for chronic management, not acute attacks.
📘 Q85 (Pharmacology) — A 39-year-old woman with newly diagnosed breast cancer is prescribed letrozole. What is the most important prerequisite before starting letrozole therapy? A) Normal liver function tests B) Postmenopausal status confirmed C) Normal renal function D) Baseline bone density scan E) Complete blood count within normal limits
Answer: B
Letrozole is an aromatase inhibitor that is effective only in postmenopausal women, as it works by inhibiting peripheral conversion of androgens to oestrogens. In premenopausal women, the ovaries produce sufficient aromatase to overcome the blockade. Therefore, premenopausal women require ovarian suppression (e.g., with GnRH agonists) or oophorectomy before aromatase inhibitor therapy. Tamoxifen is used in premenopausal women.
📘 Q86 (Pharmacology) — A 25-year-old woman presents with an anaphylactic reaction to latex during delivery. Which of the following is the first-line medication for acute anaphylaxis in pregnancy? A) Intravenous chlorphenamine B) Intramuscular adrenaline (epinephrine) C) Intravenous hydrocortisone D) Inhaled salbutamol E) Oral prednisolone
Answer: B
Intramuscular adrenaline (epinephrine) is the first-line treatment for anaphylaxis in pregnancy, as in non-pregnant patients. Adrenaline causes vasoconstriction, bronchodilation, and reduces oedema. It should be administered immediately into the anterolateral thigh. Pregnant women should be positioned in left lateral tilt to prevent aortocaval compression. Antihistamines and corticosteroids are second-line adjunctive therapies.
📘 Q87 (Pharmacology) — A 34-year-old woman with a history of alcohol misuse is prescribed disulfiram. She is planning pregnancy. Which of the following is the most appropriate advice? A) Disulfiram is safe in pregnancy B) Disulfiram should be discontinued before conception due to teratogenicity concerns C) Disulfiram can be continued until pregnancy is confirmed D) Disulfiram is only contraindicated in the first trimester E) Disulfiram causes fetal alcohol syndrome
Answer: B
Disulfiram is contraindicated in pregnancy (FDA Category C) and should be discontinued before conception. Animal studies have shown teratogenic effects, including limb defects and neural tube abnormalities. There is limited human data, but the potential risks outweigh benefits in pregnancy. Alcohol cessation counselling and alternative strategies for maintaining abstinence should be discussed.
📘 Q88 (Pharmacology) — A 28-year-old woman with hyperprolactinaemia is treated with cabergoline and successfully conceives. When should cabergoline be discontinued in pregnancy? A) Immediately upon positive pregnancy test B) At 12 weeks gestation C) At 20 weeks gestation D) At 28 weeks gestation E) Cabergoline should be continued throughout pregnancy
Answer: A
Cabergoline should be discontinued as soon as pregnancy is confirmed, as the safety of continuous use throughout pregnancy has not been established. The risk of prolactinoma expansion during pregnancy is low for microadenomas. However, in women with macroadenomas, cabergoline may be cautiously continued under specialist supervision. Bromocriptine has more safety data in pregnancy but is less well-tolerated.
📘 Q89 (Pharmacology) — A 41-year-old woman with endometrial cancer undergoes surgery and is found to have stage IB disease with high-grade histology. She is being considered for adjuvant vaginal brachytherapy. Which of the following chemotherapeutic agents is sometimes used concurrently with radiation? A) Paclitaxel B) Cisplatin C) Doxorubicin D) Cyclophosphamide E) Carboplatin
Answer: B
Cisplatin is the most common chemotherapeutic agent used as a radiosensitiser in gynaecological cancers, particularly cervical cancer. It enhances the effects of radiation by inhibiting DNA repair after radiation-induced damage. Concurrent cisplatin chemoradiation is the standard of care for locally advanced cervical cancer. This approach improves local control and overall survival compared to radiation alone.
📘 Q90 (Pharmacology) — A 32-year-old woman with a history of recurrent urinary tract infections in pregnancy is recommended antibiotic prophylaxis. Which of the following antibiotics is most appropriate for prophylaxis? A) Nitrofurantoin B) Ciprofloxacin C) Doxycycline D) Trimethoprim E) Gentamicin
Answer: A
Nitrofurantoin (50-100 mg at night) is the preferred antibiotic for UTI prophylaxis in pregnancy due to its efficacy against common uropathogens, minimal impact on gut flora, and established safety profile. It achieves high urinary concentrations with low systemic absorption. Trimethoprim is avoided in the first trimester (folate antagonist) and near term (kernicterus risk). Fluoroquinolones and tetracyclines are avoided in pregnancy.
📘 Q91 (Pharmacology) — A 26-year-old woman with heavy menstrual bleeding is considering the levonorgestrel-releasing intrauterine system (LNG-IUS, Mirena). After insertion, which of the following hormonal changes is expected? A) Significant increase in serum oestradiol B) Suppression of ovulation in most cycles C) Minimal systemic absorption with predominantly local effect D) Significant decrease in serum progesterone E) Markedly elevated FSH levels
Answer: C
The LNG-IUS releases levonorgestrel locally into the endometrial cavity, with minimal systemic absorption. The systemic hormone levels are significantly lower than with oral progestogens, which is why ovulation is not consistently suppressed and systemic side effects are minimised. The local hormonal effect causes endometrial suppression, leading to reduced menstrual bleeding or amenorrhoea over time.
📘 Q92 (Pharmacology) — A 35-year-old woman with hepatitis C is being treated with ribavirin and interferon. She is planning pregnancy. Which of the following is the most appropriate advice? A) Ribavirin is safe in pregnancy B) Both ribavirin and interferon must be discontinued 6 months before conception C) Ribavirin has a prolonged half-life and requires a washout period of at least 6 months before conception D) Interferon is the only teratogenic component E) Pregnancy is allowed once treatment is completed
Answer: C
Ribavirin is a nucleoside analogue with significant teratogenic and embryocidal effects. It has a prolonged elimination half-life and accumulates in tissues. Both men and women taking ribavirin must use effective contraception during treatment and for at least 6 months after completion due to its persistence in the body. Interferon-alpha is not significantly teratogenic but is generally avoided in pregnancy.
📘 Q93 (Pharmacology) — A 38-year-old woman is prescribed methotrexate for ectopic pregnancy. She weighs 70 kg. What dose of methotrexate is typically used for single-dose medical management? A) 25 mg/m² intramuscularly B) 50 mg/m² intramuscularly C) 75 mg/m² intramuscularly D) 100 mg/m² intramuscularly E) 150 mg/m² intramuscularly
Answer: B
The standard single-dose regimen for medical management of ectopic pregnancy is methotrexate 50 mg/m² intramuscularly. The dose is calculated based on body surface area. Day 1 treatment is followed by measurement of beta-hCG levels on Days 4 and 7. A second dose may be required if beta-hCG levels do not decline adequately. Methotrexate inhibits dihydrofolate reductase, interfering with DNA synthesis in rapidly dividing trophoblastic tissue.
📘 Q94 (Pharmacology) — A 30-year-old woman at 34 weeks gestation requires iron supplementation for iron deficiency anaemia (Hb 95 g/L, ferritin 12 μg/L). Which of the following is the most appropriate formulation? A) Oral ferrous sulphate B) Intravenous iron dextran C) Oral ferrous gluconate D) Intramuscular iron sorbitol E) Oral ferric carboxymaltose
Answer: A
Oral ferrous sulphate is the first-line treatment for iron deficiency anaemia in pregnancy due to its efficacy, safety, and low cost. It provides 65 mg of elemental iron per 200 mg tablet. Intravenous iron (e.g., ferric carboxymaltose) is reserved for women who cannot tolerate oral iron, have severe anaemia diagnosed late in pregnancy, or have malabsorption. Parenteral iron carries risks of anaphylaxis.
📘 Q95 (Pharmacology) — A 33-year-old woman with a history of recurrent ovarian cysts is prescribed the combined oral contraceptive pill for suppression. Which of the following best describes the metabolic effect of oestrogen in the COCP? A) Decreased HDL cholesterol B) Increased hepatic production of binding globulins (SHBG, CBG, TBG) C) Decreased triglyceride levels D) Increased insulin sensitivity E) Decreased coagulation factors
Answer: B
Oestrogen in the COCP stimulates hepatic synthesis of various binding globulins, including sex hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG), and thyroid-binding globulin (TBG). It also increases triglycerides and HDL cholesterol and increases coagulation factors, contributing to the thrombotic risk. The progestogen component modifies some of these effects depending on its androgenic activity.
📘 Q96 (Pharmacology) — A 40-year-old woman is diagnosed with uterine leiomyosarcoma and is being treated with gemcitabine and docetaxel. Which of the following is a common adverse effect of gemcitabine? A) Pulmonary toxicity B) Haemolytic uraemic syndrome C) Flu-like symptoms and myelosuppression D) Cardiomyopathy E) Peripheral neuropathy
Answer: C
Gemcitabine is a nucleoside analogue (pyrimidine antimetabolite) commonly associated with flu-like symptoms (fever, myalgia, headache), which can last 1-2 days, and dose-limiting myelosuppression (particularly thrombocytopenia). It also causes a mild rash and peripheral oedema. Pulmonary toxicity is less common than with bleomycin. Docetaxel is associated with peripheral neuropathy and fluid retention.
📘 Q97 (Pharmacology) — A 29-year-old woman with gestational diabetes is started on insulin. Which of the following insulin regimens is most appropriate for achieving glycaemic control in pregnancy? A) Once-daily long-acting insulin only B) Twice-daily intermediate-acting insulin (NPH) with short-acting insulin before meals C) Insulin pump therapy D) Pre-mixed insulin twice daily E) Short-acting insulin only before meals
Answer: B
The most common insulin regimen for gestational diabetes is a basal-bolus approach, typically NPH (intermediate-acting) insulin twice daily plus short-acting (rapid-acting) insulin before meals. This regimen mimics physiological insulin secretion and provides flexibility for meal timing and content. Rapid-acting analogues (lispro, aspart) are safe in pregnancy and preferred due to better postprandial control and less hypoglycaemia compared to regular insulin.
📘 Q98 (Pharmacology) — A 34-year-old woman with a history of postpartum depression is started on sertraline postpartum. Which of the following is the most important consideration when prescribing sertraline to a breastfeeding woman? A) Sertraline is contraindicated in breastfeeding B) Sertraline levels in breast milk are negligible C) Sertraline has relatively low levels in breast milk and is considered compatible with breastfeeding D) Sertraline reduces milk production E) Sertraline causes neonatal jaundice
Answer: C
Sertraline is a selective serotonin reuptake inhibitor (SSRI) with relatively low levels in breast milk and is considered one of the safest antidepressants during breastfeeding. Its active metabolite, desmethylsertraline, is also present in low concentrations. Paroxetine and fluoxetine have higher breast milk levels. The benefits of treating maternal depression generally outweigh the minimal risks to the nursing infant.
📘 Q99 (Pharmacology) — A 27-year-old woman presents with severe postpartum haemorrhage unresponsive to oxytocin. Which of the following is the most appropriate second-line agent? A) Carboprost B) Ergometrine C) Misoprostol D) Tranexamic acid E) Recombinant factor VIIa
Answer: A
Carboprost (15-methyl prostaglandin F2α) is a second-line uterotonic agent for postpartum haemorrhage refractory to oxytocin. It causes intense myometrial contractions and is administered intramuscularly (250 μg) or directly into the myometrium. It should be avoided in women with asthma as it can cause bronchospasm. Ergometrine is another option but is contraindicated in hypertension. Tranexamic acid is an adjunctive antifibrinolytic.
📘 Q100 (Pharmacology) — A 45-year-old woman with advanced ovarian cancer has developed platinum-resistant disease. She is being started on a PARP inhibitor. Which of the following best describes the mechanism of action of PARP inhibitors such as olaparib? A) Inhibition of angiogenesis B) Inhibition of DNA repair via the base excision repair pathway C) Inhibition of topoisomerase I D) Inhibition of microtubule function E) Inhibition of hormone receptor signalling
Answer: B