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.
Evaluation of efficacy of the perioperative administration of venlafaxine XR in the prevention of postmastectomy pain syndrome.
Postmastectomy pain syndrome (PMPS) is a neuropathic pain syndrome that may develop following breast surgery. Venlafaxine has been shown to be efficacious in the management of PMPS. The preemptive administration of venlafaxine has been shown to be efficacious in reducing the incidence of neuropathic pain in the rat model. We examined the efficacy of administering either venlafaxine or placebo for two weeks starting the night before surgery to 100 patients scheduled for either partial or radical mastectomy with axillary dissection. Patients were administered PCA morphine for the first 24 hours following surgery and then acetaminophen/oxycodone tablets. Pain scores were recorded at rest and movement on day 1, at 1 month, and at 6 months after surgery. At 6 months postoperatively, the presence of pain in the chest, arm, and axilla; edema; decreased sensation in the operative area; and phantom breast pain were recorded. There was no difference in postoperative opioid use. Pain scores with movement were lower in the venlafaxine group at 6 months. Pain scores at all other time intervals were similar. There was a significant decrease in the incidence of chest wall pain (55% vs. 19%, P = 0.0002), arm pain (45% vs. 17%, P = 0.003), and axilla pain (51% vs. 19%, P = 0.0009) between the control group and the venlafaxine group, respectively. No significant differences were noted between the two groups with regard to edema, phantom pain, or sensory changes. We conclude that the perioperative administration of venlafaxine beginning the night prior to surgery significantly reduces the incidence of PMPS following breast cancer surgery.