Drug interactions
St john's wort + Vincristine
Severity: Moderate
St john's wort and Vincristine: moderate 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 P-gp, which can lower vincristine exposure. This may reduce treatment efficacy.
What this interaction means in plain words
St john's wort and Vincristine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
St John's wort induces CYP3A4 and P-gp through PXR activation.
What to do
Advise patients to avoid St John's wort during chemotherapy. If it was used, note that induction persists for about two weeks after stopping.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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 Vincristine, 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.
Other interactions of Vincristine
- Adenovirus types 4 and 7 live + Vincristine Contraindicated
- Apalutamide + Vincristine Major
- Atazanavir + Vincristine Major
- Ceritinib + Vincristine Major
- Chloramphenicol + Vincristine Major
- Clarithromycin + Vincristine Major
Frequently asked questions
Can I take St john's wort with Vincristine?
MediHelp rates the interaction as moderate. St john's wort and Vincristine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. St John's wort induces CYP3A4 and P-gp, which can lower vincristine exposure. This may reduce treatment efficacy.
How serious is the interaction between St john's wort and Vincristine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid St John's wort during chemotherapy. If it was used, note that induction persists for about two weeks after stopping.
What other medicines interact with Vincristine?
MediHelp also lists interactions of Vincristine with, for example, Adenovirus types 4 and 7 live, Apalutamide, Atazanavir. The full list is on the Vincristine page.
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.
