Reduction of hyperbilirubinemia with hypericum extract (St. John's Wort) in a patient with Crigler-Najjar syndrome type II

AIMS: Crigler-Najjar syndrome (CN) type II is a congenital disease with unconjugated hyperbilirubinemia due to a deficiency of uridine 5'-diphospho-glucuronosyltransferase 1A1. Since the currently proposed treatment with phenobarbital is associated with adverse reactions, we investigated the effect of hypericum extract. METHODS: Repetitive determination of total serum bilirubin in a female with CN type II before, during and after daily treatment with 900 mg hypericum extract on two occasions for 8 weeks. Confirmation of the enzyme-inducing effect of hypericum using the cytochrome P450 3A4 probe drug i.v. midazolam. RESULTS: Hypericum reduced midazolam exposure by 42% and the total serum bilirubin concentration by 30 to 35%. CONCLUSIONS: Hypericum extract is a potential alternative to phenobarbital in patients with CN type II.