MajorCalcium channel blocker, non-DHP (benzothiazepine derivative)×Selective β1-adrenoceptor blockers
Updated · Methodology
Mechanism
Diltiazem slows AV conduction + inhibits CYP3A4 (metoprolol metabolism). Additive bradycardia and AV block.
Symptoms
Bradycardia, AV block.
Management
Avoid combination. Alternative – amlodipine.
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: Cardizem section 7 (2014)– ; DailyMed setid f3e7ecef-f360-4987-a4f5-933214130ab2
- DailyMed: Diltiazem: FDA prescribing information, Drug Interactions section (DailyMed) (2024)
- AEMPS: Ficha técnica: Metoprolol 100 mg (Aurovitas) (nº registro 82000), sección 4.5 (2026)– AEMPS, CIMA, nº registro 82000, revisión 04/2026, sección 4.5