title: Potential interaction between ritonavir and carbamazepine.
abstract: Ritonavir (RTV), a protease inhibitor, and carbamazepine (CBZ), an anticonvulsant, were administered concurrently to a patient who had human immunodeficiency virus infection and epilepsy. The combination resulted in elevated serum concentrations of CBZ, with accompanying vomiting, vertigo, and transient liver dysfunction. After discontinuing RTV and reducing the dosage of CBZ, the serum concentration of CBZ returned to the optimal range, symptoms subsided, and liver function returned to baseline. Carbamazepine is metabolized in the liver to a large extent by the cytochrome P450 (CYP) system, especially CYP3A4, 2C8, and 1A2, whereas RTV is metabolized primarily by CYP3A and is a potent inhibitor of this enzyme. Careful clinical monitoring may help prevent adverse drug interactions when these drugs are administered concurrently.
authors.affiliation: Department of Pediatrics, Hiroshima University Medical Hospital, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Fujii
authors.forename: N
authors.initials: N
authors.lastname: Mizoguchi
authors.forename: N
authors.initials: N
authors.lastname: Takata
authors.forename: K
authors.initials: K
authors.lastname: Ueda
authors.forename: M D
authors.initials: MD
authors.lastname: Feldman
authors.forename: S R
authors.initials: SR
authors.lastname: Kayser
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects*; D000927:Anticonvulsants / Q000097:blood / Q000493:pharmacokinetics*; D002220:Carbamazepine / Q000097:blood / Q000493:pharmacokinetics*; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood; D004347:Drug Interactions; D006801:Humans; D008297:Male; D019438:Ritonavir / Q000009:adverse effects*; D014717:Vertigo / Q000139:chemically induced; D014839:Vomiting / Q000139:chemically induced
chemical_list: D019380:Anti-HIV Agents; D000927:Anticonvulsants; D002220:Carbamazepine; D019438:Ritonavir