Major
Amiodarone × Rifampicin
Class III antiarrhythmics (Vaughan Williams)×Antituberculous antibiotic
Mechanism
Rifampicin strongly induces CYP3A4 – the main N-deethylation pathway of amiodarone. Amiodarone and N-desethyl-amiodarone plasma levels fall by about 50%; antiarrhythmic effect weakens.
Symptoms
Atrial fibrillation symptoms return: palpitations, irregular pulse, fatigue, dyspnoea. Rhythm breakthroughs may require admission.
Management
During anti-TB therapy, replace amiodarone with a beta-blocker for rate control or plan catheter ablation. Induction persists for 2 weeks after rifampicin stops – restart amiodarone gradually.
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.