Lamotrigine for central poststroke pain

Abstract

Objective: Central poststroke pain (CPSP) is usually difficult to treat. Amitriptyline, the only oral preparation shown to be effective in a randomized controlled trial, is often associated with a range of side effects related to the many mechanisms of actions of tricyclic antidepressants. We investigated the effect of lamotrigine, a drug that reduces neuronal hyperexcitability, on poststroke pain. Methods: Thirty consecutive patients with CPSP (median age 59 years, range 37 to 77; median pain duration 2.0 years, range 0.3 to 12) from two centers participated in a randomized, double-blind, placebo-controlled cross-over study. The study consisted of two 8-week treatment periods separated by 2 weeks of wash-out. The primary endpoint was the median value of the mean daily pain score during the last week of treatment while treated with 200 mg/d lamotrigine. Secondary endpoints were median pain scores while on lamotrigine 25 mg/d, 50 mg/d, and 100 mg/d; a global pain score; assessment of evoked pain; areas of spontaneous pain; and allodynia/dysesthesia. Results: Lamotrigine 200 mg/d reduced the median pain score to 5, compared to 7 during placebo (p = 0.01) in the intent-to-treat population of 27 patients. No significant effect was obtained at lower doses. Twelve patients (44%) responded to the treatment. There was a uniform tendency to reduction of all secondary outcome measures, but lamotrigine only had significant effects on some of the secondary outcome measures. Lamotrigine was well tolerated with few and transient side effects. Two mild rashes occurred during lamotrigine treatment, one causing withdrawal from study. Conclusions: Oral lamotrigine 200 mg daily is a well tolerated and moderately effective treatment for central poststroke pain. Lamotrigine may be an alternative to tricyclic antidepressants in the treatment of CPSP.