Diltiazem and Rifampin Interaction
Drug interaction information between Diltiazem and Rifampin.
Diltiazem and Rifampin have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Diltiazem and Rifampin. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Rifampin speeds up how quickly your body breaks down diltiazem, which can cause the diltiazem to disappear from your blood and stop working.
What To Do
You should avoid taking these two medications together.
FDA Label Information
Rifampin : Coadministration of rifampin with diltiazem lowered the diltiazem plasma concentrations to undetectable levels. Avoid coadministration of diltiazem with rifampin or any known CYP3A4 inducer.
Diltiazem Also Interacts With
- Ezetimibe major
- Ezetimibe/Simvastatin major
- Simvastatin major
- Theophylline major
- Digoxin moderate
Rifampin Also Interacts With
- Darunavir major
- Bictegravir/Emtricitabine/Tenofovir major
- Glecaprevir/Pibrentasvir major
- Nirmatrelvir/Ritonavir major
- Pitavastatin major
Frequently Asked Questions
Can I take Diltiazem and Rifampin together?
This is a moderate interaction. You should avoid taking these two medications together.
How serious is the interaction between Diltiazem and Rifampin?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Diltiazem and Rifampin interact?
Rifampin speeds up how quickly your body breaks down diltiazem, which can cause the diltiazem to disappear from your blood and stop working.
Understanding the Diltiazem and Rifampin Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Diltiazem belongs to the Calcium Channel Blocker class and Rifampin belongs to the Rifamycin Antibiotic class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Rifampin speeds up how quickly your body breaks down diltiazem, which can cause the diltiazem to disappear from your blood and stop working. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Diltiazem has 46 total documented interactions on file in this dataset, and Rifampin has 137. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: You should avoid taking these two medications together. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Diltiazem or Rifampin based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.