title: Interaction of St John's wort (Hypericum perforatum) with clozapine.
abstract: St John's wort (Hypericum perforatum) is notorious for its ability to induce the enzymes of the P450 system. Especially, it induces CYP1A2 and CYP3A4, enzymes that are closely involved in the metabolism of clozapine. We present a patient with schizophrenia, who was stable on a fixed dose with stable plasma level of clozapine, and who deteriorated after she started self-medicating with St John's wort. The reduced plasma clozapine level and the psychiatric condition normalized after the withdrawal of St John's wort. It is possible that, beside the induction of P450-enzymes, the induction of P-glycoprotein by St John's wort aggravated psychiatric deterioration of the patient. Physicians should be alert to patients self-medicating with over-the-counter medicines, especially when these medicines can lower clozapine concentrations below the therapeutic range.
authors: Department Duin & Bollenstreek, Psychiatric Centre Rivierduinen, The Netherlands. a.vanstrater@ggzduinenbollenstreek.nl
authors: Annelies C P
authors: AC
authors: Van Strater
authors: Jan P A M
authors: JP
authors: Bogers
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D003024:Clozapine / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004351:Drug Resistance; D005260:Female; D041743:Herb-Drug Interactions; D006801:Humans; D020902:Hypericum / Q000737:chemistry*; D028321:Plant Preparations / Q000009:adverse effects*; D012562:Schizophrenia, Disorganized / Q000188:drug therapy* / Q000503:physiopathology; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D028321:Plant Preparations; D003024:Clozapine