Drug interactions
Istradefylline + Simvastatin
Severity: Moderate
Istradefylline 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
At 40 mg daily istradefylline increases exposure to CYP3A4 and P-gp substrates, which may raise simvastatin levels. This increases the risk of statin myopathy, whereas the 20 mg dose showed no such effect.
What this interaction means in plain words
Istradefylline 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.
Istradefylline belongs to Central Nervous System; Simvastatin belongs to Cardiovascular.
Why it happens
Istradefylline at higher doses inhibits CYP3A4 and P-glycoprotein, reducing simvastatin metabolism and efflux.
What to do
Consider reducing the simvastatin dose when istradefylline 40 mg/day is used and monitor for muscle symptoms.
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
- Cyclosporin + Simvastatin Contraindicated
- Danazol + Simvastatin Contraindicated
- Darunavir + Simvastatin Contraindicated
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Simvastatin?
MediHelp rates the interaction as moderate. Istradefylline 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. At 40 mg daily istradefylline increases exposure to CYP3A4 and P-gp substrates, which may raise simvastatin levels. This increases the risk of statin myopathy, whereas the 20 mg dose showed no such effect.
How serious is the interaction between Istradefylline 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: Consider reducing the simvastatin dose when istradefylline 40 mg/day is used and monitor for muscle symptoms.
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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