Chronic Kidney Disease USMLE Step 1 Practice Question
A 56-year-old man with resistant hypertension (BP 168/104 mmHg) and primary hyperaldosteronism (plasma aldosterone 24 ng/dL, renin suppressed) started spironolactone 25 mg daily two months ago. He now presents with bilateral breast tenderness and mild gynecomastia. Vital signs show HR 78/min, RR 14/min, temperature 37°C. Serum potassium is 5.2 mEq/L. He denies testicular pain or libido changes. Which mechanism best explains this adverse effect?
Answer choices
- ASpironolactone irreversibly inhibits carbonic anhydrase
- BSpironolactone activates epithelial sodium channels
- CSpironolactone blocks vasopressin V2 receptors
- DSpironolactone also antagonizes androgen receptorsCorrect answer
- ESpironolactone inhibits the Na K 2Cl cotransporter
- FSpironolactone increases hepatic conversion of testosterone to estradiol
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