Oxycodone and St. John's Wort: Can You Take Them Together?

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Evidence-gradedLast reviewed June 1, 2026Source: PubMed (Nieminen et al., Eur J Pain 2010, PMID 20106684)
Learn about each ingredient:OxycodoneSt. John's Wort

Quick answer

St. John's Wort strongly induces CYP3A4, the main enzyme that metabolizes oxycodone. In a controlled crossover trial, St. John's Wort cut oral oxycodone plasma exposure (AUC) by roughly 50% and significantly reduced its analgesic effect.

Avoid combining St. John's Wort with oxycodone. Patients already taking St. John's Wort should expect inadequate pain relief and should not increase their opioid dose to compensate; instead, discontinue the herb under clinician supervision.

What happens when you take oxycodone with St. John's Wort?

Oxycodone is a strong opioid analgesic broken down in the liver primarily by the cytochrome P450 enzyme CYP3A4, with a smaller contribution from CYP2D6. St. John's Wort (Hypericum perforatum) is one of the most potent natural inducers of CYP3A4 known, largely due to its constituent hyperforin, which activates the pregnane X receptor and ramps up production of CYP3A4 and the drug transporter P-glycoprotein.

When the two are taken together, the body breaks oxycodone down faster than usual. In a placebo-controlled, randomized crossover trial published in the European Journal of Pain in 2010, healthy volunteers who took St. John's Wort three times daily for 15 days had a roughly 50% reduction in oxycodone area-under-the-curve (AUC) and a substantial drop in oxycodone's analgesic effect compared with placebo. Peak plasma concentrations also fell, and the active metabolite noroxycodone rose, consistent with accelerated CYP3A4-mediated N-demethylation.

Why is this important?

For someone using oxycodone to manage acute or chronic pain, this interaction can quietly undermine treatment. Pain that had been controlled may flare back up within one to two weeks of starting St. John's Wort, and the patient may interpret this as tolerance rather than an herb-drug interaction. The natural response is to take more oxycodone or ask the prescriber for a dose increase, both of which carry real risks.

The bigger danger appears later. CYP3A4 induction does not reverse instantly. After the herb is stopped, enzyme activity gradually returns to baseline over one to two weeks. If a clinician has titrated the oxycodone dose upward to overcome the herbal interaction, the patient is suddenly exposed to far higher opioid blood levels than they need. That can cause respiratory depression, profound sedation, and overdose, especially in people who are not opioid-tolerant or who use other CNS depressants such as benzodiazepines or alcohol.

The interaction is not limited to immediate-release oxycodone. Extended-release formulations and combination products (oxycodone with acetaminophen or naloxone) all rely on the same CYP3A4 pathway and are affected in the same way.

What should you do?

The safest approach is to avoid St. John's Wort entirely while you are taking oxycodone for pain. If you are already taking the herb, do not stop the oxycodone abruptly; instead, talk with your prescribing clinician about discontinuing the St. John's Wort and monitoring for the gradual return of opioid effect over the following one to two weeks.

If you have been on the combination and decide to stop the herb, watch carefully for signs of opioid excess: pinpoint pupils, slow or shallow breathing, deep sedation, slurred speech, or unusual nausea. Have a naloxone (Narcan) kit available, particularly if you live alone. Tell every prescriber and pharmacist about the herb; many drug interaction screening systems do not catch supplements unless you list them on your medication record.

Which specific products are affected?

This interaction applies to all branded and generic oxycodone products, including OxyContin (extended-release oxycodone), Roxicodone (immediate-release oxycodone), Percocet (oxycodone with acetaminophen), and Targin/Targiniq (oxycodone with naloxone). Other CYP3A4-metabolized opioids such as hydrocodone, fentanyl, methadone, tramadol, and buprenorphine can also be affected by St. John's Wort, though the magnitude of the interaction differs for each.

On the herbal side, the interaction is driven primarily by the hyperforin content of the preparation. Most standardized St. John's Wort extracts used for mood support (such as LI 160, WS 5570, and Ze 117) contain enough hyperforin to cause clinically significant CYP3A4 induction. Low-hyperforin extracts have been developed but are not the standard formulation sold in U.S. supplement aisles.

The bottom line

St. John's Wort can roughly halve the blood levels and pain-relieving effect of oxycodone, and the rebound when the herb is stopped can be dangerous if doses were escalated. If you take oxycodone for pain, do not start St. John's Wort. If you already take both, plan a coordinated taper of the herb with your clinician and watch closely for opioid overdose symptoms as the interaction resolves.

References

Primary evidence for this article. Always consult your healthcare provider for personal medical advice.

PubMed (Nieminen et al., Eur J Pain 2010, PMID 20106684) ↗

Reviewed June 1, 2026. How we grade evidence →

Related Topics

oxycodonest johns wortcyp3a4opioidpain managementherbal interactionenzyme inductionanalgesia

Related Interactions

Other interactions you should know about

Verapamil + St. John's Wort

high

St. John's wort is a potent inducer of intestinal CYP3A4 and P-glycoprotein. In a controlled study, two weeks of St. John's wort reduced the AUC of R- and S-verapamil by roughly 78-80%, dramatically lowering systemic drug exposure and likely therapeutic effect.

Digoxin + St. John's Wort

high

St. John's wort induces intestinal P-glycoprotein, increasing efflux of digoxin and reducing its absorption. Controlled studies show digoxin AUC falls roughly 25% and peak concentrations around 30-36% after two weeks of St. John's wort, potentially producing therapeutic failure in rate control or heart failure management.

Apixaban + St. John's Wort

high

St. John's wort strongly induces both CYP3A4 (apixaban's primary metabolizing enzyme) and P-glycoprotein (its efflux transporter). Co-use accelerates apixaban metabolism and clearance, lowering plasma concentrations and increasing the risk of stroke or thromboembolism.

Simvastatin + St. John's Wort

high

St. John's wort induces intestinal and hepatic CYP3A4 and P-glycoprotein, sharply increasing simvastatin's first-pass metabolism. In a crossover study of healthy adults, the AUC of active simvastatin hydroxy acid was cut roughly in half (to about 48% of placebo).

Sertraline + St. John's Wort

critical

Sertraline is an SSRI that blocks serotonin reuptake, and St. John's wort independently inhibits serotonin reuptake and contains constituents (hyperforin, hypericin) that elevate central serotonin. Combining them can trigger serotonin syndrome, a potentially life-threatening syndrome of altered mental status, autonomic instability, and neuromuscular hyperactivity. St. John's wort also induces CYP3A4 and CYP2C19, which can lower sertraline plasma levels and undermine treatment.

Warfarin + Dong Quai

high

Dong quai (Angelica sinensis) contains coumarin derivatives (ferulic acid, osthole) and has documented antiplatelet activity. A widely cited case report (Page & Lawrence, Pharmacotherapy 1999, PMID 10417036) described a woman whose INR rose to 4.9 within four weeks of adding dong quai 565 mg once to twice daily to stable warfarin.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider before making changes to your supplement or medication routine. Pilora does not diagnose, treat, cure, or prevent any disease.

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