Drug interactions
Istradefylline + Phenytoin
Severity: Moderate
Istradefylline and Phenytoin: 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
Phenytoin may lower istradefylline concentrations, reducing its benefit in treating OFF episodes in Parkinson's disease. The label advises avoiding strong CYP3A4 inducers.
What this interaction means in plain words
Istradefylline and Phenytoin 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; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, accelerating istradefylline metabolism.
What to do
Avoid the combination if possible and use a non-inducing antiseizure drug. If used together, monitor motor symptoms and OFF time.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Phenytoin?
MediHelp rates the interaction as moderate. Istradefylline and Phenytoin 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. Phenytoin may lower istradefylline concentrations, reducing its benefit in treating OFF episodes in Parkinson's disease. The label advises avoiding strong CYP3A4 inducers.
How serious is the interaction between Istradefylline and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible and use a non-inducing antiseizure drug. If used together, monitor motor symptoms and OFF time.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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