Topical capsaicin 8% patch in peripheral neuropathic pain: Efficacy and quality of life

Introduction: Peripheral neuropathic pain (PNP) is one of the most challenging diseases to treat with a significant negative impact on the patients' health-related quality of life (HRQoL). Capsaicin 8% patch has arisen in the last decades as an alternative to oral drugs in the treatment of PNP with fewer side effects and promising results in efficacy. Objectives: This work aims to evaluate the effectiveness of the topical application of capsaicin in PNP and its impact on patients' HRQoL based on the use of capsaicin in a tertiary hospital of Oporto. Methods: This study included 100 patients with localized PNP with poor pain control and without improvement with previous treatments that were treated at least once with an 8% capsaicin patch. Effectiveness on pain relief, number of treatments needed, safety and impact on HRQoL were assessed through a set of questionnaires. Results: Regarding the aetiology of PNP, 67.6% (N = 46) have post-surgery or trauma induced PNP with 64.7% (N = 44) of patients reporting pain in the lower limb. After the treatment, 30.9% (N = 21) felt minimally improved, 22.1 (N = 15) felt much improved and 13.2 (N = 9) felt very much improved. On a scale from 1 to 10, in the week prior to the survey, the median intensity of pain was 6 and the median interference in quality of life was 7. The majority of patients still report limitations in mobility and daily activities and moderate pain. Conclusion: Capsaicin 8% patch is effective in PNP treatment at least in the short term. Repeated applications may be important for long-term analgesia. The low systemic dose and few side effects mean that the treatment is generally well tolerated by patients. Due to the analgesic effect, capsaicin can improve the HRQoL of patients with PNP.