ModerateCalcium channel blockers (dihydropyridines)×HIV protease inhibitor / pharmacokinetic booster
Updated · Methodology
Mechanism
Ritonavir is the most potent CYP3A4 inhibitor available – the main amlodipine metabolic route. Amlodipine plasma levels rise 2- to 3-fold, with hypotension and peripheral oedema.
Symptoms
Lower blood pressure, postural dizziness, marked lower-leg oedema. Older patients: fall risk.
Management
Halve amlodipine when combined (starting 2.5 mg/day) and monitor blood pressure 1–2 weeks after. Alternative antihypertensive on ritonavir: ACE-I or ARB (no CYP3A4 dependence).
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
- AEMPS: Ficha técnica: Amlodipino (nº registro 65461), sección 4.5 (2025)– AEMPS, CIMA, nº registro 65461, revisión 08/2025, sección 4.5