Capsaicin is the chemical found in chilli peppers which makes them taste hot. It has been shown to reduce the severity of chronic pain in certain conditions such as diabetic neuropathy and post herpetic neuralgia.
Capsaicin attaches to receptors in the skin. Initially this stimulates the nerve endings, which may be perceived as an itch or burning sensation. The compund is thought to stimulate the release of substance P which is a chemical involved in the transmission of pain, from nerve terminals. This is followed by a period during which the nerve endings are less easy to stimulate as the nerve terminals become depleted of substance P, leading to loss of the pain sensation. Eventually the nerve endings are persistently desensitized which results in pain relief.
For every six patients with neuropathy, one patient would benefit from using Capsaicin 0.075%. Efficacy of topical capsaicin is moderate at best, though it may be useful for a small number of patients who are unresponsive to drug treatment.
It is important to use capsaicin cream in very small amounts as prescribed. This is applied 3-4 times a day for 8 weeks before review by your doctor.
Apply a small amount of cream to the affected area. Use your fingers to rub the cream well into the painful area. No cream should remain on the surface of the skin.
When you first use capsaicin, a warm or burning sensation may occur. This is usual. Do not reduce the number of doses as this may reduce the amount of pain relief you obtain. Capsaicin must be used regularly to work properly. If you stop using Capsaicin and the pain returns, begin using it again.
Usually about one or two weeks. However the maximum effect may take as long as 4-6 weeks. If it has not worked by this time and you have been using it regularly, it is unlikely you will derive any benefit from continued use.
One in 3 patients using capsaicin have local adverse effects. These consist mainly of burning or stinging pain or sensation of warmth at site of application. There are no serious side efects associated with Capsaicin.
Relief of pain will continue as long as you use Capsaicin. When you stop, it is likely the pain will return.
Dr Nishan Wijenaike
West Suffolk Diabetes Service