Topical Capsaicin for the Treatment of Neuropathic Pain

Neuropathic pain (NP) is an egregious problem worldwide. Due to the side-effects of oral drugs, drugs delivered directly to the affected area of pain are preferred. Capsaicin, a chemical compound isolated from chili peppers, is used as an analgesic in topical ointments and dermal patches to alleviate pain. To systematically review capsaicin's functions on NP, we retrieved articles from the PubMed database published in the last ten years. Out of 265 articles, 108 articles were selected after filtering through the inclusion and exclusion criteria. The data and knowledge currently existing for capsaicin treatment in NP are summarized. This review indicates that capsaicin effectively improves NP treatment without affecting the motor and large nerve fibers involved in sensory function. Transient receptor potential channel vanilloid type 1 (TRPV1) is the capsaicin receptor expressed in central and peripheral terminals of a sensitive primary nerve cell. Topical capsaicin has a sensible safety profile and is effective in reducing NP. Therefore, studies over the last decade suggest that capsaicin might be a potential drug for NP treatment.