Topical capsaicin (high concentration) for chronic neuropathic pain in adults

Abstract

Background This review is an update of 'Topical capsaicin (high concentration) for chronic neuropathic pain in adults' last updated in Issue 2, 2013. Topical creams with capsaicin are used to treat peripheral neuropathic pain. Following application to the skin, capsaicin causes enhanced sensitivity, followed by a period with reduced sensitivity and, after repeated applications, persistent desensitisation. High-concentration (8%) capsaicin patches were developed to increase the amount of capsaicin delivered; rapid delivery was thought to improve tolerability because cutaneous nociceptors are 'defunctionalised' quickly. The single application avoids noncompliance. Only the 8% patch formulation of capsaicin is available, with a capsaicin concentration about 100 times greater than conventional creams. High-concentration topical capsaicin is given as a single patch application to the affected part. It must be applied under highly controlled conditions, often following local anaesthetic, due to the initial intense burning sensation it causes. The benefits are expected to last for about 12 weeks, when another application might be made. Objectives To review the evidence from controlled trials on the efficacy and tolerability of topically applied, high-concentration (8%) capsaicin in chronic neuropathic pain in adults. Search methods For this update, we searched CENTRAL, MEDLINE, Embase, two clinical trials registries, and a pharmaceutical company's website to 10 June 2016. Selection criteria Randomised, double-blind, placebo-controlled studies of at least 6 weeks' duration, using high-concentration (5% or more) topical capsaicin to treat neuropathic pain. Data collection and analysis Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. Where pooled analysis was possible, we used dichotomous data to calculate risk ratio and numbers needed to treat for one additional event, using standard methods. Efficacy outcomes reflecting long-duration pain relief after a single drug application were from the Patient Global Impression of Change (PGIC) at specific points, usually 8 and 12 weeks. We also assessed average pain scores over weeks 2 to 8 and 2 to 12 and the number of participants with pain intensity reduction of at least 30% or at least 50% over baseline, and information on adverse events and withdrawals. We assessed the quality of the evidence using GRADE and created a 'Summary of findings' table. Main results We included eight studies, involving 2488 participants, two more studies and 415 more participants than the previous version of this review. Studies were of generally good methodological quality; we judged only one study at high risk of bias, due to small size. Two studies used a placebo control and six used 0.04% topical capsaicin as an 'active' placebo to help maintain blinding. Efficacy outcomes were inconsistently reported, resulting in analyses for most outcomes being based on less than complete data. For posther...

Presence of hyperalgesia predicts analgesic efficacy of topically applied capsaicin 8% in patients with peripheral neuropathic pain

“…One baseline visit up to 2 weeks before (T0) and four fol-low-up visits, 2 (T1), 4 (T2), 6 (T3) and 8 weeks (T4) after application of capsaicin (8%) were conducted. In all patients, the capsaicin (8%) patch had been applied in the painful area for 60 min (30 min when applied on feet according to the product information as well as according to previously described study protocols (for meta-analysis see Derry et al, 2013). At each visit, QST was performed in the same areas and the PDQ was completed by each subject.…”

“…Meta-analyses demonstrated 12-week-lasting efficacy after one application of capsaicin (8%) in postherpetic neuralgia and HIV-associated polyneuropathy (Derry et al, 2013;Mou et al, 2013). In other pNP syndromes, ≥30% pain relief was achieved in only about 50% of patients .…”

Capsaicin Used on Skin Influences Ion Transport Pathways: An in vitro Study

“…Capsaicin (8-methyl-N-vanillyl-6-nonenamide), a lipophilic alkaloid found in hot red chili peppers of the genus Capsicum (hot chili peppers), has long been used to treat persistent pain, such as osteoarthritic pain, postherpetic neuralgia of the trigeminal nerve, cluster headache, diabetic neuropathy, HIV-associated distal sensory neuropathy, and intractable pain in cancer patients [1,2,3,4,5,6,7,8,9,10,11,12]. Capsaicin is an agonist of transient receptor potential cation channel, subfamily V, member 1 (TRPV1), which provides the sensation of pain (nociception).…”

“…Continuous application of capsaicin produced membrane depolarization but did not evoke action potentials as a result of the process of defunctionalization of nociceptor fibers [19,20,21,22,23]. For neuropathic pain syndromes, this effect was observed to last for 12 weeks after a single 30- or 60-min capsaicin 8% path topical application [10,12,24,25,26,27,28,29,30]. …”

Alternative Medications for Medications in the Use of High‐Risk Medications in the Elderly and Potentially Harmful Drug–Disease Interactions in the Elderly Quality Measures

“…20 Topical capsaicin in high concentrations (8% patch) has been shown to be effective for postherpetic neuralgia in randomized controlled trials and is FDA approved for this use but is expensive and best considered when first-and second-line treatments have failed. 21 Capsaicin products are not effective for chronic low back pain, must be applied carefully, and can cause an unbearable burning sensation. The topical lidocaine patch is effective for postherpetic neuralgia, based on high-quality randomized controlled trials, is FDA approved for this use, and is a first-line therapy for postherpetic neuralgia.…”