Major
digoxin × hydrochlorothiazide
Cardiac glycosides (digitalis)×Thiazide diuretics
Mechanism
Thiazides cause hypokalemia and hypomagnesemia. Falling potassium and magnesium boost digoxin's arrhythmogenicity – QT prolongation and digitalis-induced rhythm disturbances.
Management
When combining, monitor electrolytes every 1–3 months. Keep potassium above 4.0 mmol/L. Alternatives include switching to a potassium-sparing diuretic or using a thiazide at low dose (12.5 mg).
Sources
- Lexicomp: Lexicomp Drug Interactions (2024)— Wolters Kluwer Clinical Drug Information, Inc. Lexi-Interact Online, 2024
- Pharmaceutical Press: Stockley's Drug Interactions, 12th edition (2024)— Preston CL (ed.). Stockley's Drug Interactions. 12th ed. London: Pharmaceutical Press; 2024