Drug interactions
Istradefylline + Mirtazapine
Severity: Minor
Istradefylline and Mirtazapine: minor 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 the 40 mg daily dose is a weak CYP3A4 inhibitor and can raise exposure to CYP3A4 substrates. Mirtazapine is partly metabolized by CYP3A4, so its levels and sedative or other adverse effects may increase. The 20 mg dose has not shown this effect.
What this interaction means in plain words
Istradefylline and Mirtazapine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Istradefylline belongs to Central Nervous System; Mirtazapine belongs to Central Nervous System.
Why it happens
Istradefylline at higher doses weakly inhibits CYP3A4, reducing mirtazapine clearance.
What to do
Monitor for excess sedation or adverse effects if istradefylline 40 mg daily is used, and consider lowering the mirtazapine dose if they occur.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Mirtazapine
- Isocarboxazid + Mirtazapine Contraindicated
- Mirtazapine + Phenelzine Contraindicated
- Mirtazapine + Pimozide Contraindicated
- Mirtazapine + Procarbazine Contraindicated
- Mirtazapine + Rasagiline Contraindicated
- Mirtazapine + Selegiline Contraindicated
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Mirtazapine?
MediHelp rates the interaction as minor. Istradefylline and Mirtazapine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Istradefylline at the 40 mg daily dose is a weak CYP3A4 inhibitor and can raise exposure to CYP3A4 substrates. Mirtazapine is partly metabolized by CYP3A4, so its levels and sedative or other adverse effects may increase. The 20 mg dose has not shown this effect.
How serious is the interaction between Istradefylline and Mirtazapine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for excess sedation or adverse effects if istradefylline 40 mg daily is used, and consider lowering the mirtazapine dose if they occur.
What other medicines interact with Mirtazapine?
MediHelp also lists interactions of Mirtazapine with, for example, Isocarboxazid, Phenelzine, Pimozide. The full list is on the Mirtazapine page.
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