Drug interactions
Diltiazem + Istradefylline
Severity: Minor
Diltiazem and Istradefylline: 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 raises exposure to CYP3A4 and P-glycoprotein substrates, which may increase diltiazem levels. At 20 mg daily this effect was not seen. Increased diltiazem exposure can cause bradycardia or hypotension.
What this interaction means in plain words
Diltiazem and Istradefylline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diltiazem belongs to Cardiovascular; Istradefylline belongs to Central Nervous System.
Why it happens
Istradefylline inhibits CYP3A4 and P-glycoprotein at higher doses, reducing diltiazem clearance.
What to do
Monitor heart rate and blood pressure if istradefylline 40 mg daily is used, and lower the diltiazem dose if needed.
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 Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Diltiazem with Istradefylline?
MediHelp rates the interaction as minor. Diltiazem and Istradefylline 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 raises exposure to CYP3A4 and P-glycoprotein substrates, which may increase diltiazem levels. At 20 mg daily this effect was not seen. Increased diltiazem exposure can cause bradycardia or hypotension.
How serious is the interaction between Diltiazem and Istradefylline?
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 heart rate and blood pressure if istradefylline 40 mg daily is used, and lower the diltiazem dose if needed.
What other medicines interact with Diltiazem?
MediHelp also lists interactions of Diltiazem with, for example, Flibanserin, Ivabradine, Lomitapide. The full list is on the Diltiazem page.
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