A patient who has heart failure receives ramipril (Altace), after which hyperkalemia develops. Which medication, administered with ramipril, can improve the patient's metabolic condition?

Ramipril is an ACE inhibitor, and a well-known adverse effect of ACE inhibitors is hyperkalemia. This occurs because ACE inhibitors reduce the production of angiotensin II, which normally stimulates aldosterone secretion. Less aldosterone means less potassium excretion by the kidneys, leading to elevated serum potassium levels. To counteract this hyperkalemia, hydrochlorothiazide is the best choice among the options listed because it is a thiazide diuretic that promotes the excretion of potassium along with sodium and water through the renal tubules, thereby lowering serum potassium. Eplerenone and spironolactone are both potassium-sparing diuretics that block aldosterone receptors. Administering either of these with an ACE inhibitor would further elevate potassium and worsen hyperkalemia, making them contraindicated in this situation. Metoprolol is a beta-blocker that treats heart failure by reducing cardiac workload; while it may be co-prescribed with ramipril, it does not directly address potassium levels and does not help correct hyperkalemia. Students should recognize that combining potassium-sparing diuretics or aldosterone antagonists with ACE inhibitors creates a dangerous additive risk of hyperkalemia, whereas thiazide or loop diuretics promote potassium loss and would be safer in this context.