Double-blind, randomized trial of bupropion SR for the treatment of neuropathic pain.

OBJECTIVE To evaluate the effectiveness and safety of bupropion sustained-release (SR) for the treatment of neuropathic pain. METHOD This single-center, outpatient, randomized, double-blind, placebo-controlled, crossover study consisted of two phases. Forty-one nondepressed patients with neuropathic pain spent 6 weeks in each phase in random order and received identical tablets of 150 mg bupropion SR or placebo. Patients were instructed to take one tablet once daily for 1 week followed by one tablet twice daily for 5 weeks. RESULTS While the patients took bupropion SR, neuropathic pain relief was improved or much improved in 30 (73%) patients, and one of these patients became pain-free. The mean average pain score at baseline was 5.7, which remained unchanged at the end of week 6 with placebo, but decreased by 1.7 points to 4.0 (p < 0.001) during therapy with bupropion SR. Pain relief with bupropion SR was significant at week 2 (p < 0.05) and continued throughout weeks 3 through 6 (p < 0.001). A significant decrease in interference of pain on quality of life was observed while patients were receiving bupropion SR compared with placebo. Side effects experienced with bupropion SR were not dose-limiting and consisted primarily of dry mouth, insomnia, headache, gastrointestinal upset, tremor, constipation, and dizziness. CONCLUSION This placebo-controlled crossover trial showed that bupropion SR (150-300 mg daily) was effective and well tolerated for the treatment of neuropathic pain.