Drug interactions
Oxycodone + St john's wort
Severity: Major
Oxycodone and St john's wort: 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 can lower oxycodone concentrations and reduce pain relief. Stopping the herb may cause oxycodone levels to rise, increasing sedation and respiratory depression risk. Serotonergic effects are also theoretically possible.
What this interaction means in plain words
Oxycodone and St john's wort 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
Induction of CYP3A4 and P-glycoprotein by St John's wort increases oxycodone clearance.
What to do
Avoid the combination where possible; if used, monitor analgesia and adjust the dose. Reduce oxycodone and monitor for toxicity if the herb is discontinued.
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 Oxycodone and St john's wort, 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 Oxycodone
- Alvimopan + Oxycodone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Oxycodone Contraindicated
- Isocarboxazid + Oxycodone Contraindicated
- Olanzapine / samidorphan + Oxycodone Contraindicated
- Oxycodone + Phenelzine Contraindicated
- Oxycodone + Sodium oxybate Contraindicated
Frequently asked questions
Can I take Oxycodone with St john's wort?
MediHelp rates the interaction as major. Oxycodone and St john's wort 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 can lower oxycodone concentrations and reduce pain relief. Stopping the herb may cause oxycodone levels to rise, increasing sedation and respiratory depression risk. Serotonergic effects are also theoretically possible.
How serious is the interaction between Oxycodone and St john's wort?
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 where possible; if used, monitor analgesia and adjust the dose. Reduce oxycodone and monitor for toxicity if the herb is discontinued.
What other medicines interact with Oxycodone?
MediHelp also lists interactions of Oxycodone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Isocarboxazid. The full list is on the Oxycodone 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.
