Efficacy of sustained-release bupropion in neuropathic pain: an open-label study.

OBJECTIVE

The purpose of this study was to assess the analgesic potential of sustained-release (SR) bupropion for neuropathic pain.

DESIGN

Open-label treatment design.

SETTING

Outpatient pain clinic, University of Arizona Health Sciences Center, Tucson, Arizona.

PATIENTS

Twenty-two patients with a diagnosis of neuropathic pain.

INTERVENTIONS

Patients with neuropathic pain received 1 week of 150 mg SR bupropion once daily followed by 7 weeks of 150 mg SR bupropion twice daily.

OUTCOME MEASURES

Treatment effects were assessed by daily ratings of pain intensity, posttreatment global ratings of pain relief, depression scores (Hamilton Depression Scale), and daily ratings of side effects.

RESULTS

Fifteen patients (68%) reported that their pain relief was improved or much improved with bupropion. The mean average pain score at week 1 was 6.7, which decreased at the end of week 8 to 5.3 (paired t test, t[df = 21]3.327; p = 0.003) in all patients studied and to 3.8 (paired t test, t[df = 14]3.754; p = 0.002) in the patients who improved. Pain relief was statistically significant at week 5 (paired t test, t[df = 21]3.816; p = 0.001) and continued throughout weeks 6, 7, and 8. Most patients were not depressed, and analgesia was observed to occur without change in depression ratings in most patients who responded. Side effects were rated as mild and consisted primarily of insomnia (8 patients), tremor (3 patients), and gastrointestinal upset (2 patients). These symptoms had a tendency to recede with continuation of therapy.

CONCLUSIONS

This uncontrolled pilot study suggests that bupropion may be an effective and tolerated treatment for some patients with neuropathic pain. Blockade of norepinephrine reuptake may mediate this effect. The role of dopamine reuptake blockade is uncertain. A larger randomized, double-blind, placebo-controlled study is currently underway to confirm these preliminary results.