Phenytoin and Ulipristal: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Phenytoin and Ulipristal unless specifically directed by your doctor.
How Phenytoin interacts with Ulipristal
Phenytoin is a potent CYP3A4 inducer that accelerates metabolism of ulipristal acetate, markedly reducing plasma concentrations and the contraceptive or emergency contraceptive effect.
What you should do
Avoid ulipristal in patients taking phenytoin or other strong enzyme inducers; use a copper intrauterine device for emergency contraception instead.
Key facts
Severity
Major — avoid combination
Mechanism
Phenytoin is a potent CYP3A4 inducer that accelerates metabolism of ulipristal acetate, markedly reducing plasma concent...
Action
Avoid ulipristal in patients taking phenytoin or other strong enzyme inducers; use a copper intrauterine device for emer...
Frequently asked questions
Can I take Phenytoin and Ulipristal together?
No — this combination should generally be avoided. Avoid ulipristal in patients taking phenytoin or other strong enzyme inducers; use a copper intrauterine device for emergency contraception instead.
What is the severity of this interaction?
The interaction between Phenytoin and Ulipristal is classified as Major — avoid combination. Phenytoin is a potent CYP3A4 inducer that accelerates metabolism of ulipristal acetate, markedly reducing plasma concentrations and the contraceptive or emergency contraceptive effect.
What should I do if I'm prescribed both?
Avoid ulipristal in patients taking phenytoin or other strong enzyme inducers; use a copper intrauterine device for emergency contraception instead. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.