Is capsaicin still being used for neuropathic pain?
Yes. Capsaicin is a naturally occurring compound that selectively depletes peptide neurotransmitters (such as substance P) from small-diameter primary afferent neurons and is toxic to the TRPV1 receptors on small axons responsible for thermal pain. Capsaicin cream has been used in PHN and in neuropathy due to HIV. A typical trial could include application to the affected area 3 to 4 times daily for 4 weeks, after which some patients may have a significant response. Due to the pain and logistics involved in typical dosing, a high-concentration (8%) capsaicin patch was approved for treatment by the FDA in 2009 that only requires application for 1 hour every 3 months, with relief lasting days to months.