The suppressive effects of oxcarbazepine on mechanical and cold allodynia in a rat model of neuropathic pain.

Oxcarbazepine (OCBZ) is a keto analog of carbamazepine (CBZ) and may have similar analgesic properties to CBZ, but studies on its effects in neuropathic pain conditions are rare. In this study, we evaluated the analgesic effects of OCBZ in a rat neuropathic pain model. Male Sprague-Dawley rats were prepared by tightly ligating the left L5 and L6 spinal nerves to produce neuropathic pain. Sixty neuropathic rats were randomly assigned into six groups, and normal saline, a vehicle (polyethylene glycol 400), and OCBZ (10 mg/kg, 20 mg/kg, 30 mg/kg, and 50 mg/kg) were intraperitoneally administered to these individual groups. Mechanical and cold allodynia were observed at preadministration and 15, 30, 60, 90, 120, 150, and 180 min after drug administration and were quantified by measuring withdrawal frequencies to stimuli with von Frey filaments and 100% acetone, respectively. Rotarod performance was measured to detect drug-induced adverse motor effects. In the OCBZ-treated groups, withdrawal frequencies to mechanical and cold stimuli were significantly reduced in a dose-dependent manner (P < 0.05). Only at the largest dose did OCBZ reduce rotarod performance time. These results suggest that OCBZ may be a possible therapeutic consideration in neuropathic pain conditions associated with allodynia and hyperalgesia.