title: Carbamazepine-risperidone interactions in patients with epilepsy.
abstract: Because concomitant administration of psychoactive and antiepileptic drugs is increasing progressively in neurologic and psychiatric practice, the aim of the current study was to evaluate the pharmacokinetic interactions between risperidone (RISP) and carbamazepine (CBZ) plasma concentrations in a group of patients with epilepsy with behavioral disturbances. The authors assessed eight patients on CBZ monotherapy (CBZ extended-release capsules) at a mean dosage of 625 +/- 253 mg/day (range, 400-1,200 mg/day) for at least 1 year. RISP (1 mg in one daily dose) was added to CBZ therapy for the occurrence of behavior disturbances. CBZ blood levels were assessed before (T0), 24 hours after (T1), and 2 weeks after (T2) RISP administration. Steady-state plasma concentrations of CBZ increased from 6.67 +/- 0.41 microg/mL at baseline to 7.37 +/- 0.59 microg/mL (p < 0.01) at T1, to 7.95 +/- 0.47 microg/mL (p < 0.0001) at T2. The pharmacokinetic data suggest either a possible role of RISP in inhibiting the cytochrome P450 microsomal enzyme system (CYP)-3A4 pathway or a potential role of CYP2D6 in CBZ metabolism.
authors: Department of Neurology, Amedeo Avogadro University, Novara, Italy.
authors: Marco
authors: M
authors: Mula
authors: Francesco
authors: F
authors: Monaco
mesh_terms: D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000097:blood / Q000493:pharmacokinetics*; D014150:Antipsychotic Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002220:Carbamazepine / Q000097:blood / Q000493:pharmacokinetics*; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism; D018967:Risperidone / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D000927:Anticonvulsants; D014150:Antipsychotic Agents; D002220:Carbamazepine; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D019389:Cytochrome P-450 CYP2D6; D051544:Cytochrome P-450 CYP3A; D018967:Risperidone