 It is also used to reduce the symptoms of peripheral neuropathy, such as post-herpetic neuralgia caused by shingles.A capsaicin transdermal patch (Qutenza) for the management of this particular therapeutic indication (pain due to post-herpetic neuralgia) was approved as a therapeutic by the U.S. FDA, but a subsequent application for Qutenza to be used as an analgesic in HIV neuralgia was refused.One 2017 review of clinical studies having limited quality found that high-dose topical capsaicin (8%) compared with control (0.4% capsaicin) provided moderate to substantial pain relief from post-herpetic neuralgia, HIV-neuropathy, and diabetic neuropathy.