MajorCalcium channel blocker, non-DHP (benzothiazepine derivative)×Antituberculous antibiotic
Updated · Methodology
Mechanism
Rifampicin is a potent inducer of drug-metabolizing enzymes and transporters, including CYP3A4 and P-glycoprotein (rifampicin label). Diltiazem is metabolized by CYP3A4 (diltiazem label). With rifampicin, diltiazem blood levels fell to undetectable (FDA diltiazem label), so its antianginal and blood pressure-lowering effect can be lost.
Symptoms
Return of hypertension, anginal episodes in ischaemic heart disease. Rate control in atrial fibrillation is lost.
Management
Avoid the combination and consider other treatment (FDA diltiazem labels). When choosing a replacement, note that nifedipine, nimodipine, nisoldipine and nitrendipine are contraindicated with rifampicin (rifampicin label). If diltiazem is kept, monitor the patient closely when rifampicin is started and after it is stopped, checking the effect of diltiazem (diltiazem labels). The diltiazem dose may need adjustment when rifampicin is started or stopped (rifampicin label).
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
- AEMPS: Ficha técnica: Diltiazem (nº registro 62328), sección 4.5 (2023)– AEMPS, CIMA, nº registro 62328, revisión 06/2023, sección 4.5
- AEMPS: Ficha técnica: Diltiazem, Masdil Retard 120 mg (nº registro 58483), sección 4.5 (2025)– AEMPS, CIMA, nº registro 58483, revisión 03/2025, sección 4.5
- FDA: Cardizem CD (diltiazem) prescribing information (2025)– FDA label, DailyMed setid 1042fa13-e6af-46b9-8008-6c941f0978b1, revised 12/2025, PRECAUTIONS: Drug Interactions
- FDA: Cardizem (diltiazem) prescribing information (2025)– FDA label, Bausch Health US LLC, DailyMed setid f3e7ecef-f360-4987-a4f5-933214130ab2, revised 04/2025, Precautions: Drug Interactions (Digitalis, Carbamazepine, Rifampin, Statins)
- AEMPS: Ficha técnica: Rifampicina (nº registro 46029), secciones 4.3 y 4.5 (2026)– AEMPS, CIMA, nº registro 46029, revisión 04/2026, secciones 4.3 y 4.5