200 mg daily of lamotrigine has no analgesic effect in neuropathic pain: a randomised, double-blind, placebo controlled trial

Abstract

Anticonvulsant drugs are commonly used in neuropathic pain. There is anecdotal evidence of an analgesic effect of the anticonvulsant lamotrigine in neuropathic pain, but this is verified by few randomised controlled trials. This randomised, double-blind, placebo controlled trial of examined the effect of lamotrigine in a dose increasing to 200 mg in 100 patients with neuropathic pain. Eight patients failed to attend for review, 18 withdrew early and 74 provided results. There was no statistical difference in age, sex or duration pre-treatment pain in the two groups. Total pain, the character of the pain, sensitivity, numbness, paraesthesia, sleep, mobility, mood, quality of life and analgesic consumption were measured. There was a correlation between burning and numbness (P<0. 01), shooting pain and total pain (P<0.01) and between analgesic consumption and mobility (P<0.05) throughout the study period. There were no correlation between any other measured variable. There was no significant change in any variable measured over the eight week period when lamotrigine was used. It is concluded that at the dose used and using the dose escalation regime described, lamotrigine had no effect on either pain, component pain symptoms or quality of life variables.