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.
Amitriptyline versus placebo in postherpetic neuralgia.
To study the effects of amitriptyline in treating postherpetic neuralgia, 24 patients were randomly assigned to either drug or placebo in a double-blind crossover study. We found good to excellent pain relief in 16 of 24 patients (p less than or equal to 0.001). We did not find an antidepressant effect in most patients (p greater than 0.05). The median dose of amitriptyline was 75 mg. The median blood level was 65 ng per milliliter, and of nortriptyline 30 ng per milliliter. Good responses were maintained in 12 of 22 patients. Amitriptyline is useful in treating postherpetic neuralgia and may not act as an antidepressant.