USMLE Pharmacology 2

Question 1

A patient taking isoniazid for TB develops peripheral neuropathy. Which vitamin supplementation prevents this?

Accepted Answer

Pyridoxine (B6)

Answer

Thiamine (B1)

Answer

Cyanocobalamin (B12)

Answer

Niacin (B3)

Question 2

Which mechanism explains why aminoglycosides are bactericidal despite being protein synthesis inhibitors?

Accepted Answer

They cause misreading of mRNA, producing abnormal proteins that disrupt cell membranes

Answer

They bind the 50S subunit and block translocation

Answer

They inhibit peptidyl transferase activity

Answer

They prevent binding of aminoacyl-tRNA

Question 3

A patient with HIV on antiretroviral therapy develops central adiposity, peripheral fat wasting, and hyperlipidemia. Which drug class causes this metabolic syndrome?

Accepted Answer

Protease inhibitors

Answer

NNRTIs

Answer

NRTIs

Answer

Integrase inhibitors

Question 4

Which anticoagulant requires no laboratory monitoring and directly inhibits thrombin (Factor IIa)?

Accepted Answer

Dabigatran

Answer

Rivaroxaban

Answer

Apixaban

Answer

Fondaparinux

Question 5

A patient develops 'red man syndrome' during IV vancomycin infusion. What is the underlying mechanism?

Accepted Answer

Direct mast cell degranulation (non-IgE mediated)

Answer

IgE-mediated type I hypersensitivity

Answer

Complement activation

Answer

Immune complex deposition

Question 6

Which diuretic acts on the thick ascending limb of the loop of Henle and inhibits the Na-K-2Cl cotransporter?

Accepted Answer

Furosemide

Answer

Hydrochlorothiazide

Answer

Spironolactone

Answer

Acetazolamide