St John'S Wort and Tacrolimus: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining St John'S Wort and Tacrolimus unless specifically directed by your doctor.
How St John'S Wort interacts with Tacrolimus
St John's wort is a potent CYP3A4 and P-glycoprotein inducer that markedly reduces tacrolimus trough levels, risking acute transplant rejection.
What you should do
Contraindicated in transplant recipients. Screen for herbal use; if stopped, monitor tacrolimus levels closely for 2-4 weeks as enzyme activity normalises.
Key facts
Severity
Major — avoid combination
Mechanism
St John's wort is a potent CYP3A4 and P-glycoprotein inducer that markedly reduces tacrolimus trough levels, risking acu...
Action
Contraindicated in transplant recipients. Screen for herbal use; if stopped, monitor tacrolimus levels closely for 2-4 w...
Frequently asked questions
Can I take St John'S Wort and Tacrolimus together?
No — this combination should generally be avoided. Contraindicated in transplant recipients. Screen for herbal use; if stopped, monitor tacrolimus levels closely for 2-4 weeks as enzyme activity normalises.
What is the severity of this interaction?
The interaction between St John'S Wort and Tacrolimus is classified as Major — avoid combination. St John's wort is a potent CYP3A4 and P-glycoprotein inducer that markedly reduces tacrolimus trough levels, risking acute transplant rejection.
What should I do if I'm prescribed both?
Contraindicated in transplant recipients. Screen for herbal use; if stopped, monitor tacrolimus levels closely for 2-4 weeks as enzyme activity normalises. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.