5% lidocaine medicated plaster in painful diabetic peripheral neuropathy (DPN): a systematic review.

BACKGROUND Several pharmacological treatments are used to manage painful diabetic peripheral neuropathy (DPN). OBJECTIVE To compare 5% lidocaine medicated plaster (5%LMP) for the relief of DPN with other relevant interventions and placebo. METHODS Six databases were searched up to June 2009. Quantitative methods for data synthesis were used and a network meta-analysis was conducted. RESULTS Twenty-three studies (38 publications) were included. One study compared 5%LMP with pregabalin and indicated the non-inferiority of 5%LMP for pain reduction. DPN patients experienced a greater improvement in quality of life when using 5%LMP compared to pregabalin. Adverse events were significantly fewer in patients treated with 5%LMP. In the network meta-analysis, all interventions remained effective in comparison with placebo (mean difference in change of pain from baseline compared with placebo, amitriptyline: -12.58 [95% CI -16.66 to -8.50]; capsaicin: -9.40 [95% CI -13.92 to -4.88]; gabapentin: -10.22 [95% CI -17.25 to -3.19]; pregabalin: -10.53 [95% CI -14.74 to -6.32]; 5%LMP: -9.10 [95% CI -13.93 to -4.26]) and 5%LMP was comparable to all other interventions (amitriptyline: 3.48 [95% CI -0.78 to 7.75]; capsaicin: 0.31 [95% CI -4.39 to 5.00]; gabapentin: 1.12 [95% CI -6.02 to 8.27]; pregabalin: 1.43 [95% CI -2.96 to 5.83]). CONCLUSIONS The results suggest that the effects in pain reduction of 5% lidocaine medicated plaster are comparable to those of amitriptyline, capsaicin, gabapentin and pregabalin. Topical agents such as 5%LMP may be associated with fewer and less clinically significant adverse events than is the case for systemic agents. However, the results are limited by the number and size of studies included, and thus further studies are needed.