Repeated administration of systemic gabapentin alleviates allodynia-like behaviors in spinally injured rats

The effect of systemic gabapentin, a novel antiepileptic and analgesic, was tested on allodynia-like behaviors in spinal cord injured rats. On the fir st day of treatment 30 mg/kg intraperitoneal gabapentin did not alleviate h yper-reactivity to mechanical and cold stimulation. The allodynia was signi ficantly reduced by 100 mg/kg gabapentin, which however, produced sedation and motor impairments. Repeated administration of 30 mg/kg gabapentin once a day produced a gradually increasing anti-allodynic effect. Total alleviat ion of mechanical allodynia was observed in most rats after the third admin istration of gabapentin. Thus, build-up of the antiallodynic effect of gaba pentin may develop through a time dependent mechanism or alternatively thro ugh a gradual accumulation of the effective central nervous system concentr ation of the drug. (C) 2000 Elsevier Science Ireland Ltd. All rights reserv ed.