MSRA MSRA Pharmacology and Prescribing 2 — Questions and Answers
Question 1: A patient prescribed gentamicin requires monitoring. Which parameters are most important to check?
- Weekly liver function tests
- Renal function and drug trough/peak levels (Correct answer)
- Monthly full blood count
- Thyroid function tests
Correct answer: Renal function and drug trough/peak levels
Gentamicin is an aminoglycoside antibiotic that is nephrotoxic and ototoxic; monitoring renal function and serum drug levels is essential to prevent toxicity.
Question 2: A patient on simvastatin is prescribed clarithromycin. What is the most significant clinical risk of this interaction?
- Reduced simvastatin efficacy
- Increased risk of myopathy and rhabdomyolysis (Correct answer)
- Elevated clarithromycin levels
- QT interval prolongation
Correct answer: Increased risk of myopathy and rhabdomyolysis
Clarithromycin inhibits CYP3A4, the enzyme responsible for simvastatin metabolism, causing statin levels to rise dramatically and increasing the risk of myopathy and rhabdomyolysis.
Question 3: A patient with a history of anaphylaxis to penicillin requires treatment for confirmed MSSA bacteraemia. Which antibiotic is most appropriate?
- Amoxicillin
- Co-amoxiclav
- Vancomycin (Correct answer)
- Cephalexin
Correct answer: Vancomycin
Patients with penicillin anaphylaxis carry a small but clinically significant cross-reactivity risk with cephalosporins; vancomycin is the safest non-beta-lactam alternative for serious staphylococcal infections.
Question 4: Which of the following medications routinely requires therapeutic drug level monitoring in clinical practice?
- Atorvastatin
- Amlodipine
- Phenytoin (Correct answer)
- Lisinopril
Correct answer: Phenytoin
Phenytoin has a narrow therapeutic index and exhibits non-linear (zero-order) pharmacokinetics at higher doses, making plasma level monitoring essential to ensure efficacy and avoid toxicity.
Question 5: A patient on long-term prednisolone is scheduled for major surgery. What is the most critical perioperative consideration?
- Stop prednisolone 48 hours before surgery
- Administer hydrocortisone cover for adrenal insufficiency (Correct answer)
- Double the prednisolone dose post-operatively
- Start a proton pump inhibitor on the day of surgery
Correct answer: Administer hydrocortisone cover for adrenal insufficiency
Long-term corticosteroid use suppresses the hypothalamic-pituitary-adrenal axis; IV hydrocortisone cover is required perioperatively to prevent an Addisonian crisis during the physiological stress of surgery.
Question 6: Which anticoagulant is the treatment of choice for a pregnant patient diagnosed with deep vein thrombosis?
- Warfarin
- Rivaroxaban
- Low molecular weight heparin (LMWH) (Correct answer)
- Aspirin
Correct answer: Low molecular weight heparin (LMWH)
LMWH (e.g., enoxaparin) does not cross the placenta and is the anticoagulant of choice in pregnancy; warfarin is teratogenic and direct oral anticoagulants are contraindicated in pregnancy.
Question 7: A patient newly started on sodium valproate requires monitoring. Which investigations are most important?
- Renal function every 6 months
- Liver function tests and full blood count (Correct answer)
- Thyroid function tests
- Serum calcium and phosphate
Correct answer: Liver function tests and full blood count
Sodium valproate can cause hepatotoxicity (especially in young children) and thrombocytopenia, so liver function tests and full blood count must be monitored regularly.
MSRA MSRA Pharmacology and Prescribing 2
A patient prescribed gentamicin requires monitoring.
Which parameters are most important to check?