The Effect of Oxcarbazepine on the Pharmacokinetics of Single-Dose Aripiprazole in a Rat Model

Background/Objectives: A possible pharmacokinetic interaction between a single dose of aripiprazole and multiple-dose pretreatment with oxcarbazepine was investigated in vivo in Wistar albino rats. Methods: The experiment was conducted on two groups of 12 male rats each. The control group received a single oral dose of aripiprazole (8 mg/kg), while the test group was given oral oxcarbazepine (85 mg/kg/day) for 5 days, followed by a single oral dose of aripiprazole (8 mg/kg). Blood samples were automatically drawn following the administration of aripiprazole to each rat. Noncompartmental analysis was employed to determine the pharmacokinetic parameters of aripiprazole and its active metabolite, dehydroaripiprazole. Results: After the five-day oxcarbazepine pretreatment, aripiprazole’s maximum plasma concentration decreased by 51.37%, and its mean half-life was significantly reduced by 1.51-fold. In contrast, for the metabolite, the mean total area under the concentration–time curve increased by 44.66%, and the mean apparent systemic clearance decreased by 61.84%. Conclusions: Multiple-dose pretreatment with oxcarbazepine resulted in significant changes in the pharmacokinetics of a single oral dose of aripiprazole and its active metabolite in vivo in rats. The clinical implications should be further studied in human subjects, as this interaction may reduce the efficacy of aripiprazole.