Objective: To establish the effects of topically applied capsaicin on daily activities in patients with painful diabetic neuropathy.
Research design and methods: Investigators at 12 sites enrolled 277 men and women with painful peripheral polyneuropathy and/or radiculopathy in an 8-wk double-blind vehicle-controlled study with parallel randomized treatment assignments. Participants were unresponsive or intolerant to conventional therapy and were experiencing pain that interfered with functional activities and/or sleep. Either 0.075% capsaicin cream or vehicle cream was applied to the painful areas 4 times/day. A visual analogue scale of pain intensity and baseline measurements of the pain's interference with the ability to walk, work, participate in recreational activities, use shoes and socks, sleep, and eat were recorded at onset and at 2-wk intervals. A physician's global evaluation scale assessed changes in pain status from baseline.
Results: Statistically significant differences are percentage of patients with improvement in favor of capsaicin versus vehicle: 69.5 vs 53.4% with clinical improvement in pain status (P = 0.012), 26.1 vs. 14.6% with improvement in walking (P = 0.029), 18.3 vs. 9.2% with improvement in working (P = 0.019), 29.5 vs. 20.3% with improvement in sleeping (P = 0.036), and 22.8 vs. 12.1% with improvement in participating in recreational activities (P = 0.037).
Conclusions: The results from this study suggest that topical 0.075% capsaicin is effective for reducing pain in patients with painful diabetic neuropathy with subsequent improvement in daily activities, enhancing the quality of the patient's life.