Repeated USMLE Questions Step 1 Review-159- Pharmacology

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Q- A patient taking allopurinol for gout should be closely monitored for which serious adverse effect?

A- Aplastic anemia

B- Hepatotoxicity

C- Severe hypersensitivity reaction

D- Thrombocytopenia

C- Severe hypersensitivity reaction- Allopurinol can cause a life-threatening hypersensitivity syndrome characterized by rash, fever, eosinophilia, and organ involvement.

 

Q- A patient with asthma is prescribed propranolol and develops worsening shortness of breath. What explains this effect?

A- Alpha-1 receptor blockade

B- Beta-1 receptor stimulation

C- Beta-2 receptor blockade

D- Muscarinic receptor activation

C- Beta-2 receptor blockade- Nonselective beta blockers like propranolol block β₂ receptors in the lungs, causing bronchoconstriction in asthmatic patients.

 

Q- Which medication reduces platelet aggregation by irreversibly inhibiting cyclooxygenase (COX)?

A- Aspirin

B- Clopidogrel

C- Dipyridamole

D- Warfarin

A- Aspirin- Aspirin irreversibly inhibits COX-1, decreasing thromboxane A₂ synthesis and platelet aggregation for the life of the platelet.

 

Q- A patient treated with morphine develops constipation. What is the primary mechanism responsible?

A- Decreased intestinal secretion

B- Decreased intestinal motility

C- Increased fluid absorption

D- Increased smooth muscle tone

B- Decreased intestinal motility- Opioids reduce GI peristalsis by acting on μ-receptors in the gut, leading to constipation.

 

Q- A patient with epilepsy is started on carbamazepine. Which laboratory abnormality should be monitored?

A- Hypercalcemia

B- Hyponatremia

C- Hypokalemia

D- Hypomagnesemia

B- Hyponatremia- Carbamazepine can cause SIADH, leading to dilutional hyponatremia.

 

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