Diltiazem and Ranolazine interaction
Diltiazem and Ranolazine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Diltiazem (DILTIAZEM HYDROCHLORIDE in SODIUM CHLORIDE) label · effective 2025-04-15
Effect of other drugs on Diltiazem Cytochrome P450 3A4 Inhibitors/ Inducers Diltiazem is a substrate of the cytochrome P450 3A4 enzyme and inhibitors/inducers may change the pharmacological effect of diltiazem Monitor.
Buspirone Carbamazepine Cyclosporine Quinidine Ranolazine Limit ranolazine to 500 mg twice daily.
• Ranolazine: Limit ranolazine to 500 mg twice daily.
From the Ranolazine (ASPRUZYO SPRINKLE) label · effective 2025-01-29
Moderate CYP3A Inhibitors Limit the dose of ASPRUZYO Sprinkle to 500 mg twice daily in patients on moderate CYP3A inhibitors, including diltiazem, verapamil, erythromycin, fluconazole, and grapefruit juice or grapefruit-containing products [see Dosage and Administration (2.2), Clinical Pharmacology (12.3)].
Moderate CYP3A inhibitors (e.g., diltiazem, verapamil, erythromycin): Limit ASPRUZYO Sprinkle to 500 mg twice daily.
Effects of Other Drugs on Ranolazine Strong CYP3A Inhibitors Concomitant use of ASPRUZYO Sprinkle with strong CYP3A inhibitors, including ketoconazole, itraconazole, clarithromycin, nefazodone, nelfinavir, ritonavir, indinavir, and saquinavir is contraindicated [see Contraindications (4), Clinical Pharmacology (12.3)].
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.