St John's Wort: A Hidden Risk for Transplant Patients

Herbal medications may cause prescription drug interactions in transplant recipients. After 2 of our kidney transplant recipients started self-medicating with St John's wort, their cyclosporine concentrations were consistently documented to be subtherapeutic. While on St John's wort, one patient developed acute rejection possibly due to low cyclosporine concentrations. Termination of St John's wort returned both patients' cyclosporine concentrations to therapeutic values. Based on the Naranjo Adverse Drug Reaction Probability Scale, our report would achieve a “probable” score, which supports the existence of a St John's wort–cyclosporine adverse drug interaction. St John's wort may induce cytochrome P-450 3A4 activity and/or P-glycoprotein expression, which are both involved in the metabolism and absorption of cyclosporine. Patients using St John's wort concomitantly with cyclosporine or other medications with similar absorption and/or metabolism to cyclosporine need close monitoring. Transplant coordinators are in a critical position to educate transplant recipients about the potential risks of herbal medication usage.

Alternative Therapy Use in Liver Transplant Recipients

Background

The extent of use of alternative therapies and the psychosocial variables predictive of their use have not been well defined in liver transplant recipients.

Objective

To determine types of alternative therapies used by liver transplant recipients and to assess psychosocial, behavioral, and quality of life variables associated with the use of alternative therapies in these patients.

Methods

Assessment of types of alternative therapies used, demographic characteristics, satisfaction with social support, coping styles, sense of personal control (mastery), quality of life, and health beliefs in 32 liver transplant recipients.

Results

Overall, 34.4% of the liver transplant recipients used a form of alternative therapy. Herbal products were used by 45% of the alternative therapy users and included milk thistle (silymarin), eclipta, and green beet leaf—all considered “hepatic tonics.” Alternative therapy users tended to have greater problem-focused coping skills than nonusers ( P = .08). Nineteen percent of the patients incurred annual out-of-pocket expense of at least $100 for alternative therapies. Patients incurring out-of-pocket expenses reported better overall health ( P = .02), were more likely to be employed ( P = .025), and had higher mastery scores ( P = .01).

Conclusions

Use of alternative therapies is common after liver transplantation. Herbal products used by liver transplant recipients are disease specific; that is, they claim to promote liver health.

Drug interaction between St. John's wort and cyclosporine

OBJECTIVE

To report a probable drug interaction between the herbal dietary supplement St. John's wort and cyclosporine.

CASE REPORT

A 29-year-old white woman who received a cadaveric kidney and pancreas transplant, with stable organ function and stable cyclosporine concentrations began self-medicating with St. John's wort. After taking St. John's wort supplements for four to eight weeks, her cyclosporine concentrations became subtherapeutic; this was associated with organ rejection. Four weeks after stopping St. John's wort, her cyclosporine concentrations again became therapeutic. Subsequent to this rejection episode, she has developed chronic rejection and now has returned to dialysis.

DISCUSSION

St. John's wort is suspected to be a significant inducer of CYP3A4 isoenzyme activity and of P-glycoprotein (P-gp) expression, both of which are important in the metabolism and absorption of cyclosporine. Cyclosporine exhibits a relatively small therapeutic window and is sensitive to medications that can modulate the CYP3A4 isoenzyme and P-gp in both the liver and small intestines.

CONCLUSIONS

Patients taking St. John's wort concomitant with other prescription medications whose absorption and metabolism are mediated by the CYP3A4 isoenzyme and P-gp require close monitoring. Patient medication histories should include inquiries into the use of herbal dietary supplements.