Capsaicin has a Long History
Capsaicin (pronounced cap-say-sin), is a chemical compound found in hot peppers, with properties that can provide pain relief but also, in some instances, cause skin irritation. It has a long history, likely dating back many years before the first official report that appeared in 1850, citing the use of hot pepper extract on burning or itching extremities. (1) This was a literal application of folk medicine’s “treating like with like”. That being said, capsaicin has been the subject of multiple studies and bears consideration as an option for topical neuropathic pain treatment.
Capsaicin is available in a variety of topical analgesic creams in concentrations ranging from 0.025% to 0.100%. Zostrix is an example of an over-the-counter product available in most pharmacies; available in 2 strengths: 0.025% and 0.075%. Continued application can provide pain reduction within a few days; however, it can take a couple of weeks to notice significant pain relief.
A high-concentration (8%) patch is only available for use under controlled conditions in a hospital or clinic. A local anesthetic is used to numb the skin before the patch is applied for up to 60 minutes. Pain relief with a single treatment of this concentration can last up to 3 months.
Earlier studies – throughout the 1980s – attributed capsaicin’s effect on reducing pain solely to stripping the nerves of a pain-signaling transmitter, Substance P. Researchers now believe that capsaicin has an additional role in reducing pain by decreasing the functionality of nociceptors, nerve cell endings that initiate pain sensations. This removes the nerve’s sensitivity to pain messages, and can be effective in reducing the chronic pain of peripheral neuropathy. (2)
The most recent double-blind studies with the 8% capsaicin patch, showed a statistically significant, although modest, reduction in pain. A bonus was the discovery that capsaicin can also improve the quality of sleep, which is often lacking in neuropathic pain sufferers. Other than local skin irritation, that usually lessens over time, capsaicin is normally well-tolerated and has none of the systemic side-effects that can be encountered with other drug treatments.
- Turnbull A. Tincture of capsaicin as a remedy for chilblains and toothache. Dublin Free Press. 1850; 1:95–6
- Topical capsaicin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patchAnand, K. Bley Br J Anaesth. 2011 Oct; 107(4): 490–502.Published online 2011 Aug 17. doi: 10.1093/bja/aer260