RESUMO
OBJECTIVE: Lignocaine is a cardiac antiarrhythmic agent occasionally used to treat neuropathic pain. This study was designed to examine the effectiveness of intravenous lignocaine in patients with intractable painful diabetic neuropathy. RESEARCH DESIGN AND METHODS: Fifteen patients with painful diabetic peripheral neuropathy, who had appeared to respond to previous lignocaine infusions, completed a double-blind, placebo-controlled crossover trial of two doses of intravenous lignocaine (5 and 7.5 mg/kg) versus saline. Infusions were administered in random order over 4 h at four weekly intervals. The effect of treatment on pain perception was assessed using the McGill Pain Questionnaire (MPQ), a daily pain diary, hours of sleep, fasting blood glucose, and use of other pain-relieving medication. RESULTS: Both doses of lignocaine significantly (P<.05 to P<.001 for the different measures) reduced the severity of pain compared with placebo. This reduction was present at both 14 and 28 days after the infusion. The qualitative nature of the pain was also significantly (P<.05 to P<.01) modified by lignocaine compared with placebo for up to 28 days. The preceding dose 4 weeks earlier significantly (P<.01 and P<.001) affected the response to the next dose. There were no significant effects of treatment on the other measures of response. There were no significant side effects of the treatment. CONCLUSIONS: This study shows that intravenous lignocaine ameliorates pain in some diabetic participants with intractable neuropathic pain who have failed to respond to or are intolerant of available conventional therapy.