Rifampin and Simvastatin Interaction
Drug interaction information between Rifampin and Simvastatin.
Rifampin and Simvastatin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Rifampin and Simvastatin. 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
Rifampin causes your body to process simvastatin more quickly, which reduces the amount of medicine in your blood.
FDA Label Information
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 A tuberculosis treatment regimen including rifampin (600 mg/day), isoniazid (300 mg/day), pyrazinamide (500 mg 3× per day), and pyridoxine (25 mg) was associated with higher than expected doses of nortriptyline were required to obtain a therapeutic drug level.
Rifampin Also Interacts With
- Darunavir major
- Bictegravir/Emtricitabine/Tenofovir major
- Glecaprevir/Pibrentasvir major
- Nirmatrelvir/Ritonavir major
- Pitavastatin major
Simvastatin Also Interacts With
- Diltiazem major
- Verapamil major
- Cyclosporine major
- Amiodarone major
- Dronedarone major
Frequently Asked Questions
What SPL severity band is on file for Rifampin + Simvastatin?
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?
Rifampin has 137 labeled pairs on file vs Simvastatin's 41. In the minor band specifically: Rifampin has 103 (also Metoprolol, Losartan, Glipizide, Propranolol); Simvastatin has 21 (also Fenofibrate, Ketoconazole, Erythromycin, Clarithromycin).
What mechanism field is on file for Rifampin and Simvastatin?
Rifampin causes your body to process simvastatin more quickly, which reduces the amount of medicine in your blood.
Simvastatin carries more major-labeled pairs than Rifampin
SPL source-record counts only. This page's band is minor · classes on file: Rifampin (Rifamycin Antibiotic); Simvastatin (HMG-CoA Reductase Inhibitor (Statin)).
Simvastatin has 11 major-labeled pairs vs Rifampin's 8. This page itself is in the minor band, not the major band.
8 major · 26 moderate · 103 minor · 137 total
- Other minor peers for Rifampin
- Metoprolol
- Losartan
- Glipizide
- Propranolol
11 major · 9 moderate · 21 minor · 41 total
- Other minor peers for Simvastatin
- Fenofibrate
- Ketoconazole
- Erythromycin
- Clarithromycin
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.