CHF3381, a novel antinociceptive agent, attenuates capsaicin-induced pain in rats.

Here, we have examined the effect of the novel antinociceptive agent CHF3381 on the development of nocifensive behaviour as well as secondary mechanical allodynia and hyperalgesia induced by intraplantar injection of capsaicin in rats. Vehicle, CHF3381 or gabapentin were orally administered 1 h before capsaicin injection. The duration of nocifensive behaviour was measured during the first 5 min after capsaicin injection. Secondary mechanical allodynia and hyperalgesia were measured at 5 and 15 min after capsaicin injection, respectively. CHF3381 produced a significant suppression of nocifensive behaviour and completely blocked the development of mechanical allodynia and hyperalgesia at 100 and 200 mg/kg. Gabapentin weakly inhibited the development of nocifensive behaviour and mechanical allodynia. On the contrary, gabapentin (100 mg/kg) completely prevented the development of mechanical hyperalgesia. In conclusion, CHF3381 had full efficacy for all the capsaicin-induced pain parameters tested, suggesting that CHF3381 may have a therapeutic utility in the management of pain states involving central sensitisation.