CriticalClass III antiarrhythmics (Vaughan Williams)×HIV protease inhibitor / pharmacokinetic booster
Updated · Methodology
Mechanism
Dual mechanism: ritonavir strongly inhibits CYP3A4, the partial clearance route of amiodarone, raising amiodarone levels. Both drugs also prolong QT. The FDA lists the combination as an absolute contraindication.
Symptoms
QT prolongation on ECG, dizziness, syncope, palpitations. Severe cases progress to torsades de pointes with risk of ventricular fibrillation and sudden cardiac death.
Management
The combination is not prescribed. For HIV-positive patients with atrial fibrillation, use a beta-blocker for rate control or catheter ablation for rhythm control. Where possible, switch antiretroviral therapy to a ritonavir-free regimen.
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: Norvir (ritonavir) prescribing information contraindications (2018)– ; DailyMed setid 2849298e-de6e-47bb-8194-56e075b33fc3
- AEMPS: Ficha técnica: Ritonavir (nº registro 81039), sección 4.5 (2025)– AEMPS, CIMA, nº registro 81039, sección 4.5