Review: tricyclic antidepressants, capsaicin, gabapentin, and oxycodone are effective for postherpetic neuralgia.

Main results 27 trials were included. 6 trials evaluated topical treatments (follow up of 2 d to 6 wk). Of 2 trials that compared a lidocaine patch with placebo, 1 showed no difference and 1 showed a reduction in pain with lidocaine. 2 trials showed greater pain relief with capsaicin 0.075% cream than with placebo. 2 trials comparing benzydamine cream with placebo showed no difference between groups for pain relief. 12 trials evaluated oral treatments (follow up of 3 wks to 6 mo). In 6 trials that assessed tricyclic antidepressants, amitriptyline was more effective than placebo (2 trials), lorazepam (1 trial), fluphenazine (1 trial), and maprotiline (1 trial) and was as effective as nortriptyline (1 trial); desipramine was more effective than benztropine (1 trial). Gabapentin was more effective than placebo for pain relief and improvement in sleep and quality of life (1 trial). Single placebo controlled trials of dextromethorphan, memantine, and acyclovir showed no difference between groups. Oxycodone was more effective than placebo for pain relief and disability scores (1 trial). 1 trial comparing tramadol with clomipramine with or without levomepromazine showed better pain relief with tramadol but no difference in pain intensity between groups. 9 trials evaluated other treatments (follow up of 8 wks to 2 y). Vincristine iontophoresis was no more effective than placebo in 1 trial and reduced pain in another small trial. Acupuncture was also not effective in 1 trial but had a short term effect in another small trial. Intrathecal methylprednisolone plus lidocaine was more effective than intrathecal lidocaine alone or no treatment (1 trial) and was more effective than epidural methylprednisolone (1 trial). 1 trial comparing a mixture of gangliosides with placebo showed improvement in pain and sleep scores with gangliosides but poor tolerability. Bupivacaine was more effective than was intravenous lidocaine for pain scores at up to 1 year (1 trial).