Furosemide

Furosemide’s exam identity is its electrolyte fallout. By forcing sodium out it drags potassium, calcium, and magnesium along with it, so expect hypokalemia (the headline risk), along with hyponatremia, hypocalcemia, and metabolic alkalosis. The single most-tested link is furosemide plus digoxin: the low potassium furosemide causes sharply raises the risk of digoxin toxicity, which is why potassium is checked before either drug is given. (Contrast loop diuretics with thiazides, which retain calcium — “loops lose calcium.”)

Because furosemide is a sulfonamide, ask about sulfa allergies. Push IV doses slowly — rapid administration, high doses, or pairing with aminoglycosides risks ototoxicity (hearing loss). For monitoring, daily weights are the most reliable measure of fluid status; also track intake and output, blood pressure, and signs of dehydration or orthostatic hypotension. On the exam, a furosemide question is usually really a potassium question — watch for muscle weakness, cramps, and cardiac dysrhythmias that signal hypokalemia.