Drug interactions
Istradefylline + Loperamide
Severity: Moderate
Istradefylline and Loperamide: 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/day increases exposure to P-gp substrates, so loperamide levels may rise. This could intensify adverse effects of loperamide including constipation and, at high exposure, cardiac effects.
What this interaction means in plain words
Istradefylline and Loperamide 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; Loperamide belongs to Gastrointestinal Tract.
Why it happens
Istradefylline inhibits P-gp, reducing loperamide efflux.
What to do
Use the lowest effective loperamide dose and monitor for excessive constipation, drowsiness or palpitations.
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 Loperamide
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Loperamide?
MediHelp rates the interaction as moderate. Istradefylline and Loperamide 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/day increases exposure to P-gp substrates, so loperamide levels may rise. This could intensify adverse effects of loperamide including constipation and, at high exposure, cardiac effects.
How serious is the interaction between Istradefylline and Loperamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective loperamide dose and monitor for excessive constipation, drowsiness or palpitations.
What other medicines interact with Loperamide?
MediHelp also lists interactions of Loperamide with, for example, Amiodarone, Amisulpride, Anagrelide. The full list is on the Loperamide page.
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