Digoxin toxicity may result from the concurrent administration of digoxin with all of the following drugs EXCEPT.: (A) Quinidine, (B) Hydrochlorothiazide, (C) Triamterene, (D) Furosemide
Answer is C. Triamterene is a potassium-sparing diuretic that may protect against diuretic-induced digoxin toxicity. Dioxin toxicity may be caused by drugs that increase serum digoxin levels or increase the binding of dioxin to its receptor, the sodium potassium adenosine tri phosphatase (ATPase). Quinidine decreases digoxin volume of distribution and clearance. Verapamil also decreases the clearance of digoxin. Both drugs may thereby increase serum digoxin levels and precipitate digoxin toxicity. Diuretics(e.g.hydrochlorothiazide, furosemide) may cause hypokalemia and hypomagnesemia, both of which may predispose to cardiac arrhythmias. Fuhermore, hypokalemia increases dioxin binding to sodium potassium ATPase.