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.
Clomipramine and amitriptyline in the treatment of severe pain.
Clomipramine is the most potent 5-HT reuptake blockade agent among the antidepressants. A comparison between the effect of clomipramine and a less powerful 5-HT reuptake blockade agent (amitriptyline) could test the hypothesis that brain 5-HT is a mediator of pain sensation. Groups of patients of either sex, with pain indication of trigeminal neuralgia, tension headache or postherpatic neuralgia, received doses of clomipramine or amitriptyline in a single blind clinical experiment. The results after three months of treatment showed that clomipramine: (1) was better than amitriptyline in treating trigeminal neuralgia; (2) tended to be better in the treatment of tension headache; and (3) amitriptyline is better in treating postherpatic neuralgia. Clomipramine was better tolerated. The results support the hypothesis that in certain pain situations, clomipramine exerts a beneficial effect, not only because of its effect on the depression and anxiety level of the patient, but also via its effects on the 5-HT brain system.