Drug interactions
St john's wort + Ulipristal
Severity: Major
St john's wort and Ulipristal: major 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
St John's wort induces CYP3A4 and lowers ulipristal concentrations. This can reduce contraceptive effectiveness of emergency contraception or the efficacy of fibroid therapy.
What this interaction means in plain words
St john's wort and Ulipristal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
St John's wort induces CYP3A4 (and P-gp), increasing ulipristal clearance.
What to do
Avoid the combination, and do not use ulipristal for emergency contraception during or shortly after St John's wort use. Choose a copper intrauterine device as the alternative.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for St john's wort and Ulipristal, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Frequently asked questions
Can I take St john's wort with Ulipristal?
MediHelp rates the interaction as major. St john's wort and Ulipristal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. St John's wort induces CYP3A4 and lowers ulipristal concentrations. This can reduce contraceptive effectiveness of emergency contraception or the efficacy of fibroid therapy.
How serious is the interaction between St john's wort and Ulipristal?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination, and do not use ulipristal for emergency contraception during or shortly after St John's wort use. Choose a copper intrauterine device as the alternative.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
