Does Rifampin Interact with Simvastatin?
Rifampin and Simvastatin have a major drug interaction according to U.S. FDA drug labeling data. Decrease AUC by 56% Narcotic Analgesics Oxycodone Decrease AUC by 86% Morphine Decrease exposure Selective 5-HT3 Receptor Antagonists Ondansetron Decrease exposure Statins Metabolized by CYP3A4 Simvastatin Decrease exposure Thiazolidinediones Rosiglitazone Decrease AUC by 66% Tricyclic Antidepressants Nortriptyline i Decrease exposure Other Drugs Enalapril Decrease active metabolite exposure Chloramphenicol j Decrease exposure Clarithromycin Decrease exposure Dapsone Decrease exposure Doxycycline k Decrease exposure Irinotecan l Prevention or Management: Avoid the use of rifampin, strong CYP3A4 inducer, if possible. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Major
- Rifampin Class
- Rifamycin Antibacterial
- Simvastatin Class
- HMG-CoA Reductase Inhibitor
- Management
- Close medical supervision required
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Rifampin and your doctor is considering prescribing Simvastatin (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask how frequently you should be monitored while these are co-prescribed
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider