Drug interactions
Ethinyl estradiol-norgestimate + Istradefylline
Severity: Minor
Ethinyl estradiol-norgestimate 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 increases exposure to sensitive CYP3A4 substrates, which may include ethinyl estradiol. No such effect was seen at 20 mg daily.
What this interaction means in plain words
Ethinyl estradiol-norgestimate 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.
Ethinyl estradiol-norgestimate belongs to Endocrine; Istradefylline belongs to Central Nervous System.
Why it happens
Istradefylline at higher doses weakly inhibits CYP3A4, reducing the clearance of ethinyl estradiol.
What to do
No adjustment is generally needed at 20 mg daily. At 40 mg daily, monitor for increased estrogenic adverse effects.
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 Ethinyl estradiol-norgestimate
- Ethinyl estradiol-norgestimate + Fezolinetant Contraindicated
- Ethinyl estradiol-norgestimate + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-norgestimate + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-norgestimate Major
- Amobarbital + Ethinyl estradiol-norgestimate Major
- Anastrozole + Ethinyl estradiol-norgestimate Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Ethinyl estradiol-norgestimate with Istradefylline?
MediHelp rates the interaction as minor. Ethinyl estradiol-norgestimate 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 increases exposure to sensitive CYP3A4 substrates, which may include ethinyl estradiol. No such effect was seen at 20 mg daily.
How serious is the interaction between Ethinyl estradiol-norgestimate 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 generally needed at 20 mg daily. At 40 mg daily, monitor for increased estrogenic adverse effects.
What other medicines interact with Ethinyl estradiol-norgestimate?
MediHelp also lists interactions of Ethinyl estradiol-norgestimate with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-norgestimate page.
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