St John's Wort supplements endanger the success of organ transplantation.
OBJECTIVE
St John's wort is one of the most popular herbal medicines, and health care professionals often are unaware that their patients take such supplements. St John's wort causes a decrease in cyclosporine levels, thus endangering the success of organ transplantations.


METHODS
Systematic review.


METHODS
Five independent computerized literature searches were conducted to identify all reports of such interactions. Data were extracted and are summarized in narrative form.


RESULTS
Eleven case reports and 2 case series were located. In most instances, causality between St John's wort and the clinical or biochemical result is well established. The mechanism of interaction between St John's wort and cyclosporine has been recently elucidated and involves both P-glycoprotein and cytochrome P 450 3A4 expression. Collectively these data leave little doubt that St John's wort interacts with cyclosporine, causing a decrease of cyclosporine blood levels and leading in several cases to transplant rejection.


CONCLUSIONS
St John's wort can endanger the success of organ transplantations. Adequate information may be the best way to avoid future incidences.
Ernst
E
E
Department of Complementary Medicine, School of Sport and Health Sciences, University of Exeter, 25 Victoria Park Rd, Exeter EX2 4NT, England. E.Ernst@ex.ac.uk
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000328:Adult; D000928:Antidepressive Agents / Q000009:adverse effects*; D016572:Cyclosporine / Q000097:blood / Q000493:pharmacokinetics*; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004347:Drug Interactions; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D016027:Heart Transplantation; D006801:Humans; D020902:Hypericum / Q000009:adverse effects*; D007166:Immunosuppressive Agents / Q000097:blood / Q000493:pharmacokinetics*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism; D016377:Organ Transplantation; D016035:Pancreas Transplantation; D010936:Plant Extracts / Q000009:adverse effects*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000928:Antidepressive Agents; D007166:Immunosuppressive Agents; D010936:Plant Extracts; D016572:Cyclosporine; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D019388:Cytochrome P-450 CYP1A2; D019389:Cytochrome P-450 CYP2D6; D051544:Cytochrome P-450 CYP3A