Is St. John's Wort Safe with Tacrolimus?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
This combination is contraindicated in transplant patients. Never initiate or stop St. John's Wort without direct medical supervision. If exposure has occurred, contact your transplant physician immediately for urgent tacrolimus level testing.
Why this interaction occurs
Tacrolimus is a narrow therapeutic index immunosuppressant metabolized almost exclusively by CYP3A4. St. John's Wort strongly induces CYP3A4, causing dramatic reductions in tacrolimus blood levels, leading to subtherapeutic immunosuppression and high risk of acute organ rejection.
Evidence
Evidence level: strong.
Data source
PubMed: PMID 38218549, PMID 38176912
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 130,929 reports mentioning Tacrolimus. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Tacrolimus + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All St. John's Wort interactions → · All Tacrolimus interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.