Drug interactions
Rifampin + Simvastatin
Severity: Moderate
Rifampin and Simvastatin: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Rifampin is a potent inducer of CYP3A4 and markedly reduces simvastatin and active metabolite exposure. The lipid-lowering effect may be substantially lost.
What this interaction means in plain words
Rifampin and Simvastatin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Rifampin induces hepatic and intestinal CYP3A4 and transporters, increasing simvastatin clearance.
What to do
Monitor lipids and consider a statin less affected by CYP3A4 induction, such as rosuvastatin or pravastatin, during rifampin therapy.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Simvastatin
- Atazanavir + Simvastatin Contraindicated
- Clarithromycin + Simvastatin Contraindicated
- Cobicistat + Simvastatin Contraindicated
- Cyclosporine + Simvastatin Contraindicated
- Cyclosporin + Simvastatin Contraindicated
- Danazol + Simvastatin Contraindicated
Frequently asked questions
Can I take Rifampin with Simvastatin?
MediHelp rates the interaction as moderate. Rifampin and Simvastatin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Rifampin is a potent inducer of CYP3A4 and markedly reduces simvastatin and active metabolite exposure. The lipid-lowering effect may be substantially lost.
How serious is the interaction between Rifampin and Simvastatin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor lipids and consider a statin less affected by CYP3A4 induction, such as rosuvastatin or pravastatin, during rifampin therapy.
What other medicines interact with Simvastatin?
MediHelp also lists interactions of Simvastatin with, for example, Atazanavir, Clarithromycin, Cobicistat. The full list is on the Simvastatin page.
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