Antiepileptics and the treatment of neuropathic pain: evidence from animal models

Neuropathic pain is characterised by both positive (hyperalgesia and allodynia) and negative (sensory deficits) symptoms and remains intractable to many commonly used analgesics. Antiepileptics are increasingly utilised in the treatment of neuropathic pain. This class of drugs works via three major mechanisms of action in order to dampen neuronal hyperexcitability within the central nervous system: potentiation of GABA transmission, reduction of glutamate-mediated excitatory transmission, and block of voltage-activated ion channels. The latter mechanism of action in particular, is exemplified by the success of the newer generation of antiepileptics such as lamotrigine and gabapentin in the clinical treatment of neuropathic pain symptoms. In the current review article, we will examine in detail, the antinociceptive effects of a diverse range of antiepileptics as tested in animal models of nerve injury. Where appropriate, we will compare these findings with their analgesic efficacy in the clinical treatment of neuropathic pain.