RESUMO
OBJECTIVES: This research was carried out to identify the synergistic effect of dexmedetomidine and ketorolac on neuropathic pain alleviation. METHODS: The anti-allodynic effect of intrathecal dexmedetomidine and ketorolac was investigated in rats after L5 spinal nerve ligation (SNL). Mechanical allodynia was assessed using Von Frey filaments. Every day for 3 consecutive days, beginning on the 10th day after SNL, behavioral tests were carried out at 1, 2, and 4 hr after drug injection. RESULTS: Significant increases in ipsilateral paw withdrawal thresholds (PWTs) were observed 1, 2, and 4 hr after drug injection in the groups of rats which received intrathecal injection of either dexmedetomidine (group D) or ketorolac (group K), compared to group S (P < 0.05). And group DK, which received simultaneous intrathecal injection of both dexmedetomidine and ketorolac, showed statistically significantly higher ipsilateral PWTs than groups D and K, which received only one of them (P < 0.05). CONCLUSIONS: The results of this research demonstrated the anti-allodynic effect of dexmedetomidine and ketorolac on neuropathic pain induced by SNL in rats. They also suggest that synergistic analgesia can be induced by the simultaneous injection of dexmedetomidine and ketorolac, and that combination therapy is an effective approach to treating chronic neuropathic pain syndrome.