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.
The analgesic effect of amitriptyline on chronic facial pain.
The efficacy of amitriptyline was evaluated in 28 patients with chronic oral-facial pain. Most of the patients had evidence of musculoskeletal pain while some had a history suggesting pain of neurogenic origin. Two patients had mixed elements of neurogenic and musculoskeletal pain. Amitriptyline was more effective than placebo in reducing pain after 4 weeks of treatment. No effect was found after only 1 week of drug administration in either dose range. When the patients were divided into depressed and non-depressed groups based on their Hamilton depression scores, amitriptyline reduced pain in the depressed and in the non-depressed groups as compared to placebo. Amitriptyline reduced the depression scores in the depressed group but had no effect on the depression scores in the non-depressed group. Thus, pain reduction was not associated with a change in mood in the non-depressed group. Amitriptyline had no effect on patients' ratings of the intensity of experimental heat stimuli. We conclude that amitriptyline is effective in the treatment of chronic oral-facial pain and that its efficacy is independent of its effects on depression. It appears that tricyclic antidepressants act in a fashion different from opiate drugs that alter the sensory discriminative component of pain.