Drug interactions
Istradefylline + Pimozide
Severity: Major
Istradefylline and Pimozide: major 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/day istradefylline inhibits CYP3A4 and may raise exposure to substrates such as pimozide. Because pimozide has a narrow margin of safety with QT prolongation, even moderate increases matter.
What this interaction means in plain words
Istradefylline and Pimozide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Istradefylline belongs to Central Nervous System; Pimozide belongs to Central Nervous System.
Why it happens
CYP3A4 inhibition by istradefylline at higher doses increases pimozide levels.
What to do
Avoid the combination if possible, or limit istradefylline to 20 mg/day and monitor ECG and QTc closely.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Pimozide?
MediHelp rates the interaction as major. Istradefylline and Pimozide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. At 40 mg/day istradefylline inhibits CYP3A4 and may raise exposure to substrates such as pimozide. Because pimozide has a narrow margin of safety with QT prolongation, even moderate increases matter.
How serious is the interaction between Istradefylline and Pimozide?
MediHelp rates it major, 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, or limit istradefylline to 20 mg/day and monitor ECG and QTc closely.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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