Drug interactions
Ethinyl estradiol-levonorgestrel + Istradefylline
Severity: Minor
Ethinyl estradiol-levonorgestrel 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 the 40 mg daily dose, istradefylline raises exposure to CYP3A4 substrates, which may increase hormone levels. The effect was not seen at 20 mg daily, and clinical consequences are likely minor.
What this interaction means in plain words
Ethinyl estradiol-levonorgestrel 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-levonorgestrel belongs to Endocrine; Istradefylline belongs to Central Nervous System.
Why it happens
Istradefylline weakly inhibits CYP3A4 at higher doses, decreasing metabolism of ethinyl estradiol and levonorgestrel.
What to do
No action is needed at 20 mg daily; with 40 mg daily, watch for estrogen or progestin adverse effects and consider the lower 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 Ethinyl estradiol-levonorgestrel
- Ethinyl estradiol-levonorgestrel + Fezolinetant Contraindicated
- Ethinyl estradiol-levonorgestrel + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-levonorgestrel + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-levonorgestrel Major
- Amobarbital + Ethinyl estradiol-levonorgestrel Major
- Anastrozole + Ethinyl estradiol-levonorgestrel Major
Other interactions of Istradefylline
Frequently asked questions
Can I take Ethinyl estradiol-levonorgestrel with Istradefylline?
MediHelp rates the interaction as minor. Ethinyl estradiol-levonorgestrel 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 the 40 mg daily dose, istradefylline raises exposure to CYP3A4 substrates, which may increase hormone levels. The effect was not seen at 20 mg daily, and clinical consequences are likely minor.
How serious is the interaction between Ethinyl estradiol-levonorgestrel 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 action is needed at 20 mg daily; with 40 mg daily, watch for estrogen or progestin adverse effects and consider the lower dose.
What other medicines interact with Ethinyl estradiol-levonorgestrel?
MediHelp also lists interactions of Ethinyl estradiol-levonorgestrel with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-levonorgestrel page.
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