Neuropathic pain in spinal cord injury: topical analgesics as a possible treatment

Study design Review of the literature and semi-structured interviews. Objective To explore the possible use of topical analgesics for the treatment of neuropathic pain (NP) in spinal cord injury (SCI). Setting Institute for Neuropathic Pain, Soest, The Netherlands. Methods A review was performed of studies on topical analgesics for SCI-related NP published up to May 2019. In addition, eight persons with SCI-related NP who were treated with topical analgesics were interviewed in a semi-structured interview on their experience with topical analgesics. Results Seven studies (five case reports and two case series) were found that evaluated the use of topical analgesics for SCI-related NP. None of the studies used a control treatment. Topical analgesics included baclofen, ketamine, lidocaine, capsaicin, and isosorbide dinitrate. All studies reported a decrease in NP over time. Persons interviewed were 49-72 years of age and all but one had an incomplete SCI. They used topical agents containing phenytoin, amitriptyline, baclofen, ketamine or loperamide. All showed a decrease in pain of at least 3 points on the 11-point numeric rating scale during this treatment. Discussion/conclusions Evidence on the use of topical analgesics in SCI is scarce. Case reports, case series and interviews suggest that the use of topical analgesics can be beneficial in treating SCI-related NP. Placebo-controlled studies are required to investigate the effect of topical analgesics on SCI-related NP.