Interaction of Hypericum perforatum (St. John's wort) with cyclosporin A metabolism in a patient after liver transplantation

Immunosuppressive therapy in patients after Fiver transplantation requires careful monitoring of blood levels for immunosuppressive agents such as cyclosporin A, A variety of drugs are capable of interfering with the metabolism of cyclosporin A. We observed a 63-year-old patient who received a liver allograft for cryptogenic liver cirrhosis in 1998, This patient developed severe acute rejection 14 months after transplantation which was associated with a sudden drop in cyclosporin A levels, Two weeks previously, he had started taking the herbal drug Hypericum perforatum (2x900 mg/day) for increasing episodes of depression. The cyclosporin A dosage later had to be doubled, which caused some side effects. Finally, an assessment of oral cyclosporin A resorption suggested an enhanced cyclosporin A metabolism. Hypericum perforatum was stopped, Both cyclosporin A dosage and blood levels immediately returned to normal, The liver function recovered completely. In conclusion, this observation is a previously undescribed drug interaction of a widely used herbal drug (Hypericum perforatum, i,e, St, John's wort) in a patient after liver transplantation.