Drug interactions
Istradefylline + Quetiapine
Severity: Moderate
Istradefylline and Quetiapine: 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
Istradefylline is a weak CYP3A4 inhibitor at higher doses and can raise exposure to CYP3A4 substrates such as quetiapine. Higher quetiapine exposure may increase sedation, orthostatic hypotension and QT effects. The effect is expected mainly at 40 mg/day of istradefylline.
What this interaction means in plain words
Istradefylline and Quetiapine 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; Quetiapine belongs to Central Nervous System.
Why it happens
Istradefylline inhibits intestinal and hepatic CYP3A4, reducing quetiapine clearance.
What to do
Monitor for sedation and hypotension when istradefylline 40 mg/day is combined with quetiapine, and consider lowering the quetiapine dose if adverse effects appear.
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 Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Quetiapine?
MediHelp rates the interaction as moderate. Istradefylline and Quetiapine 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 is a weak CYP3A4 inhibitor at higher doses and can raise exposure to CYP3A4 substrates such as quetiapine. Higher quetiapine exposure may increase sedation, orthostatic hypotension and QT effects. The effect is expected mainly at 40 mg/day of istradefylline.
How serious is the interaction between Istradefylline and Quetiapine?
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 for sedation and hypotension when istradefylline 40 mg/day is combined with quetiapine, and consider lowering the quetiapine dose if adverse effects appear.
What other medicines interact with Quetiapine?
MediHelp also lists interactions of Quetiapine with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Quetiapine page.
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