Drug interactions
Istradefylline + Tolterodine
Severity: Minor
Istradefylline and Tolterodine: 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 40 mg daily weakly inhibits CYP3A4 and may modestly raise tolterodine exposure. The effect is small because CYP2D6 is the main clearance pathway.
What this interaction means in plain words
Istradefylline and Tolterodine 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; Tolterodine belongs to Genitourinary.
Why it happens
Weak CYP3A4 inhibition by istradefylline at higher doses.
What to do
No routine adjustment; monitor for anticholinergic effects if istradefylline 40 mg is used.
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 Tolterodine
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Tolterodine?
MediHelp rates the interaction as minor. Istradefylline and Tolterodine 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 40 mg daily weakly inhibits CYP3A4 and may modestly raise tolterodine exposure. The effect is small because CYP2D6 is the main clearance pathway.
How serious is the interaction between Istradefylline and Tolterodine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine adjustment; monitor for anticholinergic effects if istradefylline 40 mg is used.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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