MajorClass III antiarrhythmic×Thiazide diuretics
Updated · Methodology
Mechanism
Hydrochlorothiazide (thiazide diuretic) increases urinary potassium loss. Low potassium amplifies dronedarone's QT effect.
Symptoms
QT prolongation on ECG. Dizziness, syncope, palpitations. Severe cases: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia and hypomagnesaemia.
Management
The combination is common (hypertension + atrial fibrillation). Check potassium and magnesium every 3 months; if potassium drops below 4.0 mmol/L, add a potassium-sparing diuretic or potassium supplement.
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: Multaq (dronedarone) prescribing information (2020)– ; DailyMed setid 7fa41601-7fb5-4155-8e50-2ae903f0d2d6
- AEMPS: Ficha técnica: Hidroclorotiazida (nº registro 86487), sección 4.5 (2026)– AEMPS, CIMA, nº registro 86487, revisión 09/2026, sección 4.5