Practice question from Cardiovascular Pharmacotherapy Basics

Which TWO lab values must be monitored closely when a patient is taking both lisinopril and spironolactone? A. Sodium and calcium B. Potassium and creatinine C. Magnesium and phosphorus D. Glucose and uric acid E. ALT and AST

Answer

B

Explanation

Both ACE inhibitors (lisinopril) and mineralocorticoid receptor antagonists (spironolactone) can cause HYPERKALEMIA. ACE inhibitors reduce aldosterone secretion (which normally promotes K+ excretion), and spironolactone directly blocks aldosterone receptors. The combination significantly increases hyperkalemia risk. Additionally, both drugs can worsen renal function, so serum creatinine should be monitored. Check potassium and creatinine at baseline, 1-2 weeks after starting/titrating, then periodically (every 3-6 months). Hold spironolactone if K+ >5.0 mEq/L or CrCl <30 mL/min. This combination is frequently tested on NAPLEX as it's common in heart failure management but requires vigilant monitoring.

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