Drug interactions
Estradiol + Istradefylline
Severity: Minor
Estradiol 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
At 40 mg daily, istradefylline raises exposure to CYP3A4 substrates, which may increase estradiol levels. At 20 mg daily this effect was not seen.
What this interaction means in plain words
Estradiol 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.
Estradiol belongs to Endocrine; Istradefylline belongs to Central Nervous System.
Why it happens
Dose-dependent weak CYP3A4 inhibition by istradefylline reduces estradiol metabolism.
What to do
No adjustment is usually needed at 20 mg daily; at 40 mg daily monitor for estrogenic adverse effects and consider reducing the estradiol dose.
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 Estradiol
- Anastrozole + Estradiol Contraindicated
- Estradiol + Fezolinetant Contraindicated
- Estradiol + Ospemifene Contraindicated
- Antithrombin alfa + Estradiol Major
- Antithrombin iii + Estradiol Major
- Estradiol + Exemestane Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Estradiol with Istradefylline?
MediHelp rates the interaction as minor. Estradiol 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. At 40 mg daily, istradefylline raises exposure to CYP3A4 substrates, which may increase estradiol levels. At 20 mg daily this effect was not seen.
How serious is the interaction between Estradiol 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: No adjustment is usually needed at 20 mg daily; at 40 mg daily monitor for estrogenic adverse effects and consider reducing the estradiol dose.
What other medicines interact with Estradiol?
MediHelp also lists interactions of Estradiol with, for example, Anastrozole, Fezolinetant, Ospemifene. The full list is on the Estradiol page.
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