Aim: To investigate the potential benefit of topical capsaicin formulations. Materials & methods: A narrative systematic review was employed. Results: About 8% capsaicin patches were found to significantly reduce symptoms of diabetic peripheral neuropathy. Capsaicin was found to improve sleep quality (p = 0.02). Capsaicin patch exposure for 60 min showed significant reduction in symptoms (-32.8%). Capsaicin cream significantly reduced pain at weeks two and six (p = 0.003 and p = 0.03, respectively), but not at week eight in comparative studies. 0.025% capsaicin gel had an insignificant reduction in pain compared with placebo (p = 0.53), however 0.075% was found to be significant (p = 0.038). Capsaicin cream did not have superior improvement of pain as compared with clonidine gel (p = 0.931). The most common adverse events included application site discomfort, erythema and burning. Conclusion: Topical capsaicin treatments are a potentially beneficial peripherally acting medication. Further research is needed to determine the best means of ameliorating the side effects of treatments.
Keywords: analgesia; complementary therapy; neuropathic pain; pain management; peripheral neuropathies; pharmacology.
Painful diabetic neuropathy (DPN) is a serious and common problem affecting those suffering from diabetes. Current treatments of DPN include medications that act on the CNS, rather than the distally affected nerves. Topical capsaicin patches and creams offer potential as alternative treatments to centrally acting neuropathy medications. Topical capsaicin depletes the neurotransmitter for pain signaling at the distally affected nerves. Topical capsaicin in all formulations has been shown to be beneficial in reduction of DPN. However, capsaicin treatments are often irritating to the skin, causing burning and redness at the application site.