Repeated USMLE Questions Step 1 Review-163- Pharmacology

Q- A patient taking warfarin is given vitamin K. What is the primary effect of vitamin K administration?

A- Decreases synthesis of clotting factors II, VII, IX, X

B- Increases synthesis of clotting factors II, VII, IX, X

C- Inhibits platelet aggregation

D- Prevents fibrin degradation

B- Increases synthesis of clotting factors II, VII, IX, X- Vitamin K reverses warfarin by restoring gamma-carboxylation of vitamin K–dependent clotting factors.

 

Q- A patient taking spironolactone develops breast enlargement and sexual dysfunction. What is the mechanism behind this adverse effect?

A- Androgen receptor stimulation

B- Antiandrogen effect

C- Calcium channel blockade

D- Serotonin receptor activation-

B- Antiandrogen effect – Spironolactone blocks androgen receptors, decreasing the effects of testosterone, which can cause gynecomastia and decreased libido.

 

Q- A patient treated with ciprofloxacin develops tendon pain and swelling. What is the most likely complication?

A- Achilles tendon rupture

B- Aplastic anemia

C- Cardiomyopathy

D- Hemolytic anemia

A- Achilles tendon rupture – Fluoroquinolones increase risk of tendinitis and tendon rupture, especially the Achilles tendon.

 

Q- A patient with asthma is started on montelukast. What is the mechanism of action of this medication?

A- Blocks leukotriene receptors

B- Inhibits cyclooxygenase

C- Stimulates beta-2 receptors

D- Stimulates muscarinic receptors

A- Blocks leukotriene receptors – Montelukast blocks CysLT1 receptors, reducing bronchoconstriction and inflammation in asthma.

 

Q- A patient receiving heparin develops thrombocytopenia and thrombosis. What is the underlying mechanism?

A- Antibody formation against heparin–platelet factor 4 complex

B- Bone marrow suppression

C- Direct platelet destruction by heparin

D- Inhibition of platelet cyclooxygenase

A- Antibody formation against heparin–platelet factor 4 complex – HIT is immune-mediated and paradoxically causes thrombosis despite low platelets.

 

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