Pharmacology and Mechanism of Action Flashcards

A patient on warfarin starts amiodarone. What is the primary mechanism of the resulting increased INR?

Answer: Inhibition of CYP2C9 metabolism of warfarin

Amiodarone inhibits CYP2C9 (and CYP3A4), reducing warfarin metabolism and raising INR.

Which mechanism explains why ACE inhibitors can cause a dry cough?

Answer: Accumulation of bradykinin and substance P

ACE normally degrades bradykinin, so its inhibition raises bradykinin levels, triggering cough.

Metformin's primary glucose-lowering mechanism is best described as:

Answer: Decreasing hepatic gluconeogenesis

Metformin chiefly reduces hepatic glucose production via AMPK activation.

Which drug class works by irreversibly inhibiting the proton pump (H+/K+ ATPase)?

Answer: Proton pump inhibitors

PPIs covalently bind and irreversibly inhibit gastric H+/K+ ATPase.

The antiplatelet effect of clopidogrel requires which step?

Answer: CYP2C19 activation to its active metabolite

Clopidogrel is a prodrug activated mainly by CYP2C19; poor metabolizers respond less.

Which mechanism underlies the bronchodilation produced by albuterol?

Answer: Beta-2 adrenergic receptor agonism increasing cAMP

Albuterol stimulates beta-2 receptors, raising cAMP and relaxing airway smooth muscle.

Statins lower LDL primarily by:

Answer: Inhibiting HMG-CoA reductase and upregulating LDL receptors

Statins inhibit HMG-CoA reductase, lowering intracellular cholesterol and upregulating hepatic LDL receptors.