Pharmacokinetics of gabapentin after single, oral administration in domestic rabbits (Oryctolagus cuniculus)

Abstract

Background: Gabapentin is used to treat seizures, neuropathic pain, and anxiety. Currently, dosage recommendations for rabbits are extrapolated from other species. The objective of this study was to determine the pharmacokinetics of gabapentin after single, oral administration in domestic rabbits. Methods: A randomized, crossover study was performed in male (n = 3) and female (n = 3) rabbits after administration of either 25 or 50 mg/kg gabapentin orally. Plasma concentrations of gabapentin were measured at 0, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 8, 12, 24, and 48 hours post-administration via liquid chromatography. Results: Mean maximum plasma concentrations were 17.70 and 16.83 µg/mL for the 25 and 50 mg/kg doses, respectively. Mean times to maximum plasma concentration were 1.75 and 1.5 hours, and mean terminal half-lives were 10.2 and 9.44 hours for the 25 and 50 mg/kg doses, respectively. No adverse effects observed at either dose. Conclusions and clinical relevance: A single oral dose of gabapentin at 50 mg/kg did not result in higher plasma concentrations compared to the 25 mg/kg dose and no differences were observed between males and females for either dosing group (P > 0.9).