The neuroleptics as adjuvant analgesics.

The role of neuroleptic drugs as adjuvant analgesics has been a subject of longstanding controversy. Despite frequent claims of efficacy, evidence from controlled trials supports neither claims of intrinsic analgesic properties nor the routine use of the neuroleptics as a means to reliably induce clinically useful analgesia. Methotrimeprazine is unique in that there is evidence for reliable dose-related analgesia that is comparable to opioid-mediated analgesia, although routine use is not recommended. Despite probable interaction with opioid receptors, there is insufficient evidence to support a role for the butyrophenone category of neuroleptics as adjuvant analgesics. Limited trials of the neuroleptics may be considered for pain that has been unresponsive to more conventional pharmacologic approaches, especially when associated with headache, nerve injury, or psychological distress. The neuroleptics have an important role in the symptomatic management of agitation, delirium, and nausea, particularly in patients with cancer.