Anticonvulsants for neuropathic pain and detoxification
Edward C. Covington, MDAddress reprint requests to E.C.C., Department of Chronic Pain Rehabilitation, P57, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195.
Anticonvulsants have been used for treatment of neuropathic pain almost as long as they have been used for seizures. Bergouignan successfully treated trigeminal neuralgia with phenytoin in 1942.1 Though it subsequently became a standard agent for this pain disorder, phenytoin use was limited by the fact that it often loses efficacy over time, and the high doses required for therapeutic activity often cause unacceptable side effects. Nonetheless, this was the beginning of the current, widely accepted use of anticonvulsant drugs to treat neuropathic pain. Since the 1960s, anticonvulsant agents have been used extensively for pain management, particularly for lancinating or burning pain of neuropathic origin. Carbamazepine is one of the most effective drugs and often the first-line agent in the treatment of trigeminal neuralgia. But today, two drugs are expanding the utility of anticonvulsant drugs: valproate, which is better tolerated, and the newer agent gabapentin, which has a unique and safer pharmacokinetic profile. Although not officially approved for use in pain therapy, there is substantial documentation for the clinical efficacy of these drugs in the treatment of neuropathic pain syndromes.
Phenytoin also has a long history of use in the treatment of alcohol withdrawal seizures. Although the efficacy of phenytoin in easing alcohol withdrawal is now in doubt, some of the newer anticonvulsants have been shown to essentially reverse signs and symptoms of alcohol and sedative withdrawal. In this summary, the older drugs phenytoin, carbamazepine, clonazepam, and valproic acid, and two newer agents gabapentin and lamotrigine are discussed and their. . .