MajorPotassium-sparing diuretics (mineralocorticoid receptor antagonists)×Calcineurin inhibitor (immunosuppressant)
Updated · Methodology
Mechanism
Spironolactone retains potassium via aldosterone receptor blockade. Tacrolimus reduces renal potassium secretion via a distal tubular inhibitory effect. Additive hyperkalaemia.
Symptoms
Muscle weakness, paraesthesia, slowed pulse, arrhythmias. ECG: peaked T waves, widened QRS. Severe cases progress to cardiac arrest.
Management
Avoid the combination in transplant patients. Alternative diuretics: furosemide (loop, removes potassium) or hydrochlorothiazide. If spironolactone is needed, check potassium and creatinine every 1–2 weeks.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Prograf (tacrolimus) prescribing information (2013)– ; DailyMed setid 7f667de1-9dfa-4bd6-8ba0-15ee2d78873b
- AEMPS: Ficha técnica: Tacrolimus (nº registro 84607), sección 4.5 (2026)– AEMPS, CIMA, nº registro 84607, revisión 03/2026, sección 4.5