SPINAL GABAPENTIN IS ANTINOCICEPTIVE IN THE RAT FORMALIN TEST

Gabapentin is a novel anticonvulsant that may be of value for the reli ef of clinical pain. To determine whether gabapentin is antinociceptiv e after spinal administration, the drug was given via an intrathecal c atheter in doses from 6 to 200 mu g/rat 10 min prior to intraplantar f ormalin. Five percent formalin injected subcutaneously in the right hi nd paw produced a biphasic reaction consisting of flinching and lickin g behaviors (phase 1, 0-10 min; phase 2, 10-60 min). Gabapentin dose-d ependently reduced the numbers of flinches and the duration of licking during phase 2 of the formalin test. The highest dose of gabapentin ( 200 mu g/rat) did not affect the tail-flick response. These results de monstrate that spinal gabapentin is antinociceptive in the formalin te st. (C) 1997 Elsevier Science Ireland Ltd.