NAPLEX QBANK Pharmacology and Mechanism of Action 2

Question 1

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

Accepted Answer

Inhibition of CYP2C9 metabolism of warfarin

Answer

Displacement of warfarin from albumin only

Answer

Induction of vitamin K epoxide reductase

Answer

Increased renal clearance of warfarin

Question 2

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

Accepted Answer

Accumulation of bradykinin and substance P

Answer

Direct beta-2 receptor blockade

Answer

Increased angiotensin II levels

Answer

Histamine release from mast cells

Question 3

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

Accepted Answer

Decreasing hepatic gluconeogenesis

Answer

Stimulating pancreatic insulin secretion

Answer

Blocking intestinal alpha-glucosidase

Answer

Inhibiting SGLT2 in the kidney

Question 4

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

Accepted Answer

Proton pump inhibitors

Answer

H2-receptor antagonists

Answer

Antacids

Answer

Prostaglandin analogs

Question 5

The antiplatelet effect of clopidogrel requires which step?

Accepted Answer

CYP2C19 activation to its active metabolite

Answer

Direct reversible binding to P2Y12

Answer

Conversion by gut bacteria

Answer

Inhibition of cyclooxygenase-1

Question 6

Which mechanism underlies the bronchodilation produced by albuterol?

Accepted Answer

Beta-2 adrenergic receptor agonism increasing cAMP

Answer

Muscarinic receptor antagonism

Answer

Phosphodiesterase inhibition

Answer

Leukotriene receptor blockade

Question 7

Statins lower LDL primarily by:

Accepted Answer

Inhibiting HMG-CoA reductase and upregulating LDL receptors

Answer

Binding bile acids in the intestine

Answer

Blocking intestinal cholesterol absorption

Answer

Inhibiting PCSK9