Drug interactions
Istradefylline + Levonorgestrel
Severity: Minor
Istradefylline and Levonorgestrel: 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 weakly inhibits CYP3A4 and may increase levonorgestrel exposure, whereas 20 mg daily has not shown this effect. Any clinical consequence is expected to be small.
What this interaction means in plain words
Istradefylline and Levonorgestrel 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; Levonorgestrel belongs to Endocrine.
Why it happens
Dose-dependent CYP3A4 inhibition by istradefylline lowers levonorgestrel clearance.
What to do
No dose change is generally needed; monitor for progestogenic adverse effects if istradefylline 40 mg daily is used.
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 Levonorgestrel
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Levonorgestrel?
MediHelp rates the interaction as minor. Istradefylline and Levonorgestrel 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 weakly inhibits CYP3A4 and may increase levonorgestrel exposure, whereas 20 mg daily has not shown this effect. Any clinical consequence is expected to be small.
How serious is the interaction between Istradefylline and Levonorgestrel?
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 dose change is generally needed; monitor for progestogenic adverse effects if istradefylline 40 mg daily is used.
What other medicines interact with Levonorgestrel?
MediHelp also lists interactions of Levonorgestrel with, for example, Amobarbital, Apalutamide, Belzutifan. The full list is on the Levonorgestrel page.
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