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 effectively relieves neuropathic pain following treatment of breast cancer.
The effectiveness of amitriptyline in relieving neuropathic pain following treatment of breast cancer was studied in 15 patients in a randomised, double-blind placebo-controlled crossover study. The dose was escalated from 25 mg to 100 mg per day in 4 weeks. The placebo and amitriptyline phases were separated by a 2-week wash-out period. Visual analogue and verbal rating scales were used for the assessment of pain intensity and pain relief. Other measures included the number of daily activities disturbed by the pain, the Finnish McGill Pain Questionnaire, adverse effects, anxiety, depression, pressure threshold and grip strength. Amitriptyline significantly relieved neuropathic pain both in the arm and around the breast scar. Eight out of 15 patients had a more than 50% decrease in the pain intensity ('good responders') with a median dose of 50 mg of amitriptyline. The 7 patients who had a less than 50% effect had drug concentrations equaling those of the good responders. The 'poor responders' reported significantly more adverse effects with amitriptyline and placebo than the good responders. It is concluded that amitriptyline effectively reduced neuropathic pain following treatment of breast cancer. However, the adverse effects of amitriptyline put most of the patients off from using the drug regularly.