Capsaicin (Axsain / Zacin) is an approved cream used for the temporary relief of pain due to by peripheral neuropathy, which can be caused by HIV infection or treatment, herpes virus or diabetes. Capsaicin is a naturally occurring chemical that produces the ‘hot’ flavour chilli peppers. It works by interrupting the transmission of pain impulses from the affected area of the skin to the brain, and by causing the pain-sensitive nerve fibres to die back temporarily.

Capsaicin is manufactured by Euroderma under the trade name Axsain or, in the United States, Zostrix.

Some studies have failed to show a benefit of capsaicin cream in patients with HIV-associated neuropathy, with high drop-out rates, primarily due to the side-effects of burning sensations on the skin^[1]. However, a recent study using skin patches containing 8% capsaicin in patients with neuropathy as a side-effect of HIV treatment has been more promising. In this trial, a local anaesthetic was applied to the skin before the patch was applied for up to 90 minutes, with pain reduction being observed for over twelve weeks after a single application. The patches were well tolerated, with only 3% of the patients needing to remove the patches early because of burning sensations^[2].

Capsaicin patches are not yet available commercially, but may be a useful treatment for HIV-related peripheral neuropathy in the future.