There are preliminary data regarding the effectiveness of topically applied antidepressants for pain. Two randomized controlled trials demonstrated topical doxepin 3-5 is analgesic in a mixed group of patients with neuropathic pain 73, 74 . In a 3 week randomized placebo controlled trial, the concentration of amitriptyline 2 ketamine 1 was not better than placebo 75 however a higher concentration of amitriptyline 4 ketamine 2 was significantly better than placebo in post herpetic neuralgia 76 .