Ranolazine and Diltiazem Interaction
Drug interaction information between Ranolazine and Diltiazem.
Ranolazine and Diltiazem have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Ranolazine and Diltiazem. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Diltiazem slows down the body's ability to process ranolazine, which can cause the drug to build up to higher levels.
FDA Label Information
7 DRUG INTERACTIONS Moderate CYP3A inhibitors (e.g., diltiazem, verapamil, erythromycin): Limit ranolazine to 500 mg twice daily. Moderate CYP3A Inhibitors Limit the dose of ranolazine 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) ].
Ranolazine Also Interacts With
- Ketoconazole major
- Carbamazepine major
- Clarithromycin major
- Rifampin major
- Phenytoin major
Diltiazem Also Interacts With
- Ezetimibe major
- Ezetimibe/Simvastatin major
- Simvastatin major
- Theophylline major
- Rifampin moderate
Frequently Asked Questions
What SPL severity band is on file for Ranolazine + Diltiazem?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Diltiazem has 46 labeled pairs on file vs Ranolazine's 31. In the minor band specifically: Ranolazine has 12 (also Fluconazole, Verapamil, Cyclosporine, Erythromycin); Diltiazem has 35 (also Buspirone, Pravastatin, Lovastatin, Cyclosporine).
What mechanism field is on file for Ranolazine and Diltiazem?
Diltiazem slows down the body's ability to process ranolazine, which can cause the drug to build up to higher levels.
Ranolazine carries more major-labeled pairs than Diltiazem
SPL source-record counts only. This page's band is minor · classes on file: Ranolazine (Late Sodium Current Inhibitor (Antianginal)); Diltiazem (Calcium Channel Blocker).
Ranolazine has 12 major-labeled pairs vs Diltiazem's 4. This page itself is in the minor band, not the major band.
12 major · 7 moderate · 12 minor · 31 total
- Other minor peers for Ranolazine
- Fluconazole
- Verapamil
- Cyclosporine
- Erythromycin
4 major · 7 moderate · 35 minor · 46 total
- Other minor peers for Diltiazem
- Buspirone
- Pravastatin
- Lovastatin
- Cyclosporine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.