Drug interactions
Istradefylline + Primaquine
Severity: Moderate
Istradefylline and Primaquine: 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 at 40 mg daily raises exposure to CYP3A4 substrates, and primaquine is partly metabolized by this enzyme. Primaquine levels may increase, with a greater risk of dose-related adverse effects such as GI upset, hemolysis or methemoglobinemia.
What this interaction means in plain words
Istradefylline and Primaquine 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; Primaquine belongs to Anti Parasitic.
Why it happens
Inhibition of CYP3A4 metabolism of primaquine by istradefylline.
What to do
Monitor for primaquine toxicity including hemolysis and methemoglobinemia, particularly with the 40 mg istradefylline dose. Consider reducing the istradefylline dose to 20 mg if appropriate.
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 Primaquine
- Pimozide + Primaquine Contraindicated
- Amiodarone + Primaquine Major
- Amisulpride + Primaquine Major
- Anagrelide + Primaquine Major
- Arsenic trioxide + Primaquine Major
- Asenapine + Primaquine Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Primaquine?
MediHelp rates the interaction as moderate. Istradefylline and Primaquine 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 at 40 mg daily raises exposure to CYP3A4 substrates, and primaquine is partly metabolized by this enzyme. Primaquine levels may increase, with a greater risk of dose-related adverse effects such as GI upset, hemolysis or methemoglobinemia.
How serious is the interaction between Istradefylline and Primaquine?
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 primaquine toxicity including hemolysis and methemoglobinemia, particularly with the 40 mg istradefylline dose. Consider reducing the istradefylline dose to 20 mg if appropriate.
What other medicines interact with Primaquine?
MediHelp also lists interactions of Primaquine with, for example, Pimozide, Amiodarone, Amisulpride. The full list is on the Primaquine page.
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