Major
diltiazem × Metoprolol
Calcium channel blocker, non-DHP (benzothiazepine derivative)×Selective β1-adrenoceptor blockers
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.