Topical analgesics for neuropathic pain: An Evidence-Informed guide for the practicing clinician

Objective To evaluate available evidence regarding efficacy and safety of topical analgesics for neuropathic pain and offer treatment guidance. Methods An expert panel searched PubMed (Medline) and reference lists of published articles for available literature assessing 8 categories of topical analgesics used to treat various neuropathic pain conditions. The panel rated the level of analgesic efficacy evidence for each treatment and considered safety, ease of use, and cost. Degree of consensus among panelists regarding recommendations was measured. Results There was strong evidence and high consensus that capsaicin 8% is effective for diabetic peripheral neuropathy and postherpetic neuralgia, and lidocaine is effective for postherpetic neuralgia. There was strong evidence and moderate consensus that capsaicin 8% may be effective for HIV-induced neuropathy. There was moderate evidence and high consensus that lidocaine is likely effective for diabetic peripheral neuropathy, idiopathic neuropathy, and post-surgical neuropathy and that capsaicin 8% may be effective for chemotherapy-induced peripheral neuropathy and complex regional pain syndrome. Evidence was weak for other topical medications, though the panel strongly agreed that antidepressants may help with postherpetic neuralgia, complex regional pain syndrome, post-surgical neuropathy, and post-traumatic neuropathy; that non-steroidal anti-inflammatory drugs may help with post-surgical neuropathy; and that gabapentin may benefit vulvodynia. There was less agreement whether antidepressants may benefit diabetic peripheral neuropathy, chemotherapy-induced peripheral neuropathy, and vulvodynia and whether capsaicin 8% could be effective for post-surgical neuropathy. Conclusions Recommendations were based on a survey and grading of existing literature and, when strong evidence was lacking, the collective clinical expertise of panelists.