title: No effect of the anticholinergic drugs trihexyphenidyl and biperiden on the plasma concentrations of bromperidol and its reduced metabolite.
abstract: Effects of the anticholinergic drugs trihexyphenidyl and biperiden on plasma concentrations of bromperidol and its reduced metabolite were studied. Subjects comprised 20 schizophrenic inpatients taking bromperidol, 6-18 mg/ day for 1-9 weeks. Patients were randomly allocated to one of two treatment sequences: trihexyphenidyl-biperiden (n = 12) or biperiden-trihexyphenidyl (n = 8). Each sequence consisted of two 2-week phases, with no washout period between the two phases. The daily dose of trihexyphenidyl was 8 mg and that of biperiden 6 mg. Plasma concentrations of bromperidol and reduced bromperidol were measured using high-performance liquid chromatography (HPLC). There was no significant difference in plasma bromperidol or reduced bromperidol concentrations among baseline, trihexyphenidyl and biperiden phases: 7.3 +/- 3.7 versus 7.2 +/- 4.1 versus 7.0 +/- 4.3 ng/ml and 2.0 +/- 2.1 versus 2.2 +/- 2.1 versus 1.9 +/- 2.0 ng/ml, respectively. The present study thus suggests that neither trihexyphenidyl nor biperiden affects plasma concentrations of bromperidol and its reduced metabolite.
authors.affiliation: Department of Neuropsychiatry, Hirosaki University Hospital, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Otani
authors.forename: M
authors.initials: M
authors.lastname: Ishida
authors.forename: N
authors.initials: N
authors.lastname: Yasui
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: K
authors.initials: K
authors.lastname: Mihara
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Kaneko
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
authors.forename: M
authors.initials: M
authors.lastname: Shibata
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D001712:Biperiden / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D006220:Haloperidol / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000188:drug therapy*; D014282:Trihexyphenidyl / Q000494:pharmacology*
chemical_list: D001712:Biperiden; D014282:Trihexyphenidyl; D006220:Haloperidol; C006820:bromperidol