A prospective identification of neuropathic pain in specific chronic polyneuropathy syndromes and response to pharmacological therapy.

Although many pharmacological agents are used in the therapy of neuropathic pain (NeP) due to polyneuropathy (PN), there are limited comparison studies comparing these agents. We evaluated patients with PN and related NeP in a tertiary care neuromuscular clinic with prospective follow-up after 3 and 6 months for degree of NeP using a Visual Analog Score (VAS). Clinical response to specific open-label pharmacotherapies was measured and compared for those patients not receiving pharmacotherapy. The severity of PN was quantified by the Toronto Clinical Scoring System (TCSS), with patients classified according to etiology of PN. Of a total of 408 patients referred for diagnosis and/or management of PN, NeP was identified in 182 patients (45%). NeP was most prevalent in patients with alcohol-associated PN. Pharmacotherapy management was provided in 91% of cases at first visit, and for 87% of cases after 6 months of follow-up. There were no serious adverse events for patients related to any medications, which included gabapentinoids, tricyclic antidepressants, anticonvulsants, cannabinoids and topical agents. Prevalence of intolerable side effects was similar amongst groups of medications. Approximated numbers needed to treat were similar between different individual oral pharmacotherapies, trending towards greater treatment efficacy with combination therapy. NeP is common in patients with PN and frequently requires pharmacotherapy management, which may be more effective with combination therapy. Future studies assessing longer duration of follow-up and quality of life changes with the use of various pharmacotherapies for management of NeP due to PN will be important.