ANTIALLODYNIC AND ANTIHYPERALGESIC EFFECTS OF NSAIDS COMBINATION IN SCIATIC NERVE LIGATION-INDUCED NEUROPATHIC PAIN IN THE RATS

Neuropathic pain (NP) has been considered as the most debilitating painful condition, the mechanisms underlying the neuropathic pain are not fully understood, but experiments on animal’s models indicate that both peripheral and central mechanisms have been involved in the pathogenesis of neuropathic pain. NP is characterized by behavioral symptoms of allodynia (pain in response to which actually do not evoke pain) and hyperalgesia (an exaggerated response to noxious stimuli). The NSAIDS are effective, inexpensive, and long-acting drugs, but their degree of analgesia is limited by the adverse effects at high doses,common ones are gastritis, gastrointestinal hemorrhage and ulceration. The prevalent belief that non-steroidal anti-inflammatory drugs (NSAIDs) lack efficacy for the treatment of neuropathic pain is so widely accepted that current neuropathic pain treatment guidelines either do not mention this class of medications or simply state that evidence of efficacy is limited or lacking. Yet, recent reports suggest that patients with neuropathic pain are at least as likely—and sometimes considerably more likely—to use NSAIDs than they are to use medications with wellestablished efficacy. There are growing evidence that central COX playsa key role in development and maintenance of neuropathic pain as evident by significantly increased immunoreactivity of COX-1 and COX-2 in superficial laminae cells in the ipsilateral spinal cord of rats with spinal nerve ligation.