Ethinylestradiol and Phenytoin: Drug Interaction Guide

Quick answer: This combination requires caution. Ethinylestradiol and Phenytoin can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Ethinylestradiol interacts with Phenytoin

Phenytoin induces CYP3A4 and glucuronidation pathways, accelerating metabolism of ethinylestradiol and reducing hormonal contraceptive efficacy.

What you should do

Use a contraceptive method unaffected by enzyme induction, such as an appropriate intrauterine method. Continue additional precautions for the recommended period after phenytoin discontinuation.

Key facts

Severity

Moderate — caution required

Mechanism

Phenytoin induces CYP3A4 and glucuronidation pathways, accelerating metabolism of ethinylestradiol and reducing hormonal...

Action

Use a contraceptive method unaffected by enzyme induction, such as an appropriate intrauterine method. Continue addition...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Ethinylestradiol and Phenytoin together?

With caution. Use a contraceptive method unaffected by enzyme induction, such as an appropriate intrauterine method. Continue additional precautions for the recommended period after phenytoin discontinuation.

What is the severity of this interaction?

The interaction between Ethinylestradiol and Phenytoin is classified as Moderate — caution required. Phenytoin induces CYP3A4 and glucuronidation pathways, accelerating metabolism of ethinylestradiol and reducing hormonal contraceptive efficacy.

What should I do if I'm prescribed both?

Use a contraceptive method unaffected by enzyme induction, such as an appropriate intrauterine method. Continue additional precautions for the recommended period after phenytoin discontinuation. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.