Pharmacology Flashcards

A drug with a narrow therapeutic index requires careful monitoring. Which of the following is the best example of a narrow therapeutic index drug?

Answer: Digoxin

Digoxin has a narrow therapeutic range (0.5–2 ng/mL); toxicity manifests with cardiac arrhythmias and visual disturbances at slightly suprathe rapeutic levels.

Which drug class is the mechanism of clopidogrel's antiplatelet effect?

Answer: Irreversible P2Y12 ADP receptor antagonist

Clopidogrel is a prodrug converted to an active metabolite that irreversibly binds and blocks the P2Y12 ADP receptor on platelets.

What is the mechanism of action of aminoglycosides?

Answer: Bind the 30S ribosomal subunit, causing misreading of mRNA

Aminoglycosides bind the 16S rRNA of the 30S subunit, causing codon misreading and premature termination of protein synthesis.

Which phase II metabolic reaction involves conjugation with glucuronic acid?

Answer: Glucuronidation

Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGTs), conjugates glucuronic acid to drugs to increase water solubility for excretion.

A patient on lithium is started on a thiazide diuretic. What is the expected outcome?

Answer: Lithium toxicity due to increased renal reabsorption

Thiazides cause sodium depletion, prompting the kidney to reabsorb more sodium and lithium together in the proximal tubule, increasing lithium levels.

Which immunosuppressant acts by inhibiting calcineurin, thereby blocking IL-2 transcription?

Answer: Cyclosporine

Cyclosporine binds cyclophilin to form a complex that inhibits calcineurin, preventing NFAT dephosphorylation and IL-2 gene transcription.

A patient develops 'red man syndrome' during vancomycin infusion. What is the recommended management?

Answer: Slow the infusion rate and pretreat with antihistamines

Red man syndrome is a rate-related infusion reaction; slowing the infusion and premedication with diphenhydramine prevents and manages this non-immune reaction.