This update has provided additional confirmation on the effectiveness of antidepressants for neuropathic pain and has provided new information on another antidepressant - venlafaxine. There is still limited evidence for the role of SSRIs. Whether antidepressants prevent the development of neuropathic pain (pre-emptive use) is still unclear. Both TCAs and venlafaxine have NNTs of approximately three. This means that for approximately every three patients with neuropathic pain who are treated with either of these antidepressants, one will get at least moderate pain relief. There is evidence to suggest that other antidepressants may be effective but numbers of participants are insufficient to calculate robust NNTs. SSRIs are generally better tolerated by patients and more high quality studies are required.
Nortriptyline versus amitriptyline in postherpetic neuralgia: a randomized trial.
OBJECTIVE (BACKGROUND): Amitriptyline (AT) is a standard therapy for postherpetic neuralgia (PHN). Our hypothesis was that nortriptyline (NT), a noradrenergic metabolite of AT, may be more effective.
                A randomized, double-blind, crossover trial of AT versus NT was conducted in 33 patients.
                Thirty-one patients completed the trial. Twenty-one of 31 (67.7%) had at least a good response to AT or NT, or both. We found no difference with regard to relief of steady, brief, or skin pain by visual analog scales for pain and pain relief; mood; disability; satisfaction; or preference between the two drugs. Intolerable side effects were more common with AT. Most patients (26/33) were not depressed, and most responding showed no change in rating scales for depression despite the occurrence of pain relief.
                We concluded that this study provides a scientific basis for an analgesic action of NT in PHN because pain relief occurred without an antidepressant effect, and that although there were fewer side effects with NT, AT and NT appear to have a similar analgesic action for most individuals.