Antipsychotics for acute and chronic pain in adults.

CONTEXT The role of antipsychotics as adjuvant analgesics is a subject of long-standing controversy. Antipsychotics have been used to treat chronic pain (e.g., chronic headache, fibromyalgia, and painful diabetic neuropathy). With atypical antipsychotics, a new class of antipsychotics, with fewer extrapyramidal side effects and additional benefits, may be available. OBJECTIVES This review aimed to assess analgesic efficacy and adverse effects of antipsychotics in acute or chronic pain. METHODS Randomized controlled trials of adults prescribed any dose of oral antipsychotics for acute or chronic pain, describing subjective pain assessment as either the primary or a secondary outcome, were included in this review. RESULTS We included 11 studies involving a total number of 770 participants. Data from five randomized, double-blind studies showed beneficial effects of antipsychotics in the treatment of acute and chronic pain. Because of the clinical heterogeneity of painful conditions studied and significant statistical heterogeneity, the intended meta-analysis was omitted. The most frequently reported adverse effects were extrapyramidal (i.e., involuntary movements, parkinsonism, and akathisia) and sedating effects. CONCLUSION Because of limitations in the available evidence, further research is needed to understand whether antipsychotics are effective for acute or chronic pain or specific pain conditions.