Drug interactions
Istradefylline + Tadalafil
Severity: Minor
Istradefylline and Tadalafil: 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/day weakly inhibits CYP3A4 and may raise tadalafil exposure, increasing adverse effects such as hypotension and headache. At 20 mg/day the effect appears absent.
What this interaction means in plain words
Istradefylline and Tadalafil 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; Tadalafil belongs to Genitourinary.
Why it happens
Dose-dependent CYP3A4 inhibition by istradefylline reduces tadalafil clearance.
What to do
Consider a lower tadalafil dose if istradefylline 40 mg/day is used, and monitor for hypotension and headache.
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 Tadalafil
- Amyl nitrite + Tadalafil Contraindicated
- Isosorbide dinitrate + Tadalafil Contraindicated
- Isosorbide mononitrate + Tadalafil Contraindicated
- Nitroglycerin po + Tadalafil Contraindicated
- Nitroglycerin rectal + Tadalafil Contraindicated
- Nitroglycerin sublingual + Tadalafil Contraindicated
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Tadalafil?
MediHelp rates the interaction as minor. Istradefylline and Tadalafil 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/day weakly inhibits CYP3A4 and may raise tadalafil exposure, increasing adverse effects such as hypotension and headache. At 20 mg/day the effect appears absent.
How serious is the interaction between Istradefylline and Tadalafil?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Consider a lower tadalafil dose if istradefylline 40 mg/day is used, and monitor for hypotension and headache.
What other medicines interact with Tadalafil?
MediHelp also lists interactions of Tadalafil with, for example, Amyl nitrite, Isosorbide dinitrate, Isosorbide mononitrate. The full list is on the Tadalafil page.
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