Update on gabapentin therapy of neuropathic pain

To provide current information regarding the efficacy and tolerability of the anticonvulsant gabapentin in the management of neuropathic pain.

A MEDLINE search was conducted to identify pertinent studies, case reports, letters, and reviews in the English language published from 1986 through October 2002. Additional references were obtained from the bibliographies of these articles.

All studies evaluating any aspect of use of gabapentin as an analgesic.

Numerous case reports and series (total N = 750) have suggested efficacy of gabapentin in daily doses of up to 3.6 g. Controlled trials in painful diabetic neuropathy, postherpetic neuralgia, and multiple sclerosis have confirmed the potential utility of this agent in a variety of neuropathic pain syndromes (total N = 511). Central nervous system side effects are of most concern with gabapentin. The absence of significant drug-drug interactions makes this agent a preferred treatment choice, as opposed to anticonvulsants such as carbamazepine or lamotrigine.

In human pain models using patients with neuropathic pain, gabapentin has been found effective against both spontaneous and evoked pain, and these effects are independent of the pain source. Gabapentin, in doses ranging up to 3.6 g/day, has demonstrated efficacy in a variety of neuropathic pain states, including those refractory to agents such as the tricyclic antidepressants (TCA) and other anticonvulsants. A major question today is whether gabapentin should be considered as first-line therapy (i.e., even before a trial of a TCA or carbamazepine) or as second-line therapy for individuals unresponsive to or intolerant of TCAs and/or carbamazepine.