Pharmacology Flashcards
6 cards from real USMLE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pharmacology flashcards as text
A patient on warfarin develops supratherapeutic INR after starting a new antibiotic. Which mechanism best explains this interaction?
Answer: Inhibition of CYP2C9 by the antibiotic
Many antibiotics inhibit CYP2C9, which metabolizes warfarin, leading to decreased warfarin clearance and elevated INR.
Which beta-blocker is cardioselective and preferred in a patient with COPD requiring beta-blockade?
Answer: Metoprolol
Metoprolol is a beta-1 selective blocker, making it safer in COPD patients by minimizing beta-2 bronchospasm compared to non-selective agents.
A patient with type 2 diabetes develops lactic acidosis. Which medication is most likely responsible?
Answer: Metformin
Metformin can cause lactic acidosis, particularly in patients with renal insufficiency, hepatic disease, or conditions causing tissue hypoperfusion.
Which antiepileptic drug works by blocking voltage-gated sodium channels and is also used for neuropathic pain and bipolar disorder?
Answer: Carbamazepine
Carbamazepine blocks voltage-gated sodium channels and is used for partial seizures, trigeminal neuralgia, and bipolar disorder.
A patient develops gynecomastia while taking spironolactone. What is the mechanism of this side effect?
Answer: Antagonism of androgen receptors
Spironolactone non-selectively antagonizes androgen receptors in addition to mineralocorticoid receptors, causing gynecomastia and sexual dysfunction in males.
Which ACE inhibitor side effect is class-specific and due to bradykinin accumulation?
Answer: Dry cough
ACE inhibitors prevent bradykinin degradation, causing dry cough in up to 15% of patients; ARBs do not inhibit bradykinin breakdown and lack this side effect.