Treatments for Acute Pain: A Systematic Review
Authors: Chou Roger , Wagner Jesse , Ahmed Azrah Y. , Blazina Ian , Brodt Erika , Buckley David I. , Cheney Tamara P. , Choo Esther , Dana Tracy , Gordon Debra , Khandelwal Saurabh , Kantner Shelby , McDonagh Marian S. , Sedgley Christine , Skelly Andrea C. 
Published: December 2020

Objectives. To evaluate the effectiveness and comparative effectiveness of opioid, nonopioid pharmacologic, and nonpharmacologic therapy in patients with specific types of acute pain, including effects on pain, function, quality of life, adverse events, and long-term use of opioids. Data sources. Electronic databases (Ovid® MEDLINE®, PsycINFO®, Embase®, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews) to August 2020, reference lists, and a Federal Register notice. Review methods. Using predefined criteria and dual review, we selected randomized controlled trials (RCTs) of outpatient therapies for eight acute pain conditions: low back pain, neck pain, other musculoskeletal pain, neuropathic pain, postoperative pain following discharge, dental pain (surgical or nonsurgical), pain due to kidney stones, and pain due to sickle cell disease. Meta-analyses were conducted on pharmacologic therapy for dental pain and kidney stone pain, and likelihood of repeat or rescue medication use and adverse events. The magnitude of effects was classified as small, moderate, or large using previously defined criteria, and strength of evidence was assessed. Results. One hundred eighty-three RCTs on the comparative effectiveness of therapies for acute pain were included. Opioid therapy was probably less effective than nonsteroidal anti-inflammatory drugs (NSAIDs) for surgical dental pain and kidney stones, and might be similarly effective as NSAIDs for low back pain. Opioids and NSAIDs were more effective than acetaminophen for surgical dental pain, but opioids were less effective than acetaminophen for kidney stone pain. For postoperative pain, opioids were associated with increased likelihood of repeat or rescue analgesic use, but effects on pain intensity were inconsistent. Being prescribed an opioid for acute low back pain or postoperative pain was associated with increased likelihood of use of opioids at long-term followup versus not being prescribed, based on observational studies. Heat therapy was probably effective for acute low back pain, spinal manipulation might be effective for acute back pain with radiculopathy, acupressure might be effective for acute musculoskeletal pain, an opioid might be effective for acute neuropathic pain, massage might be effective for some types of postoperative pain, and a cervical collar or exercise might be effective for acute neck pain with radiculopathy. Most studies had methodological limitations. Effect sizes were primarily small to moderate for pain, the most commonly evaluated outcome. Opioids were associated with increased risk of short-term adverse events versus NSAIDs or acetaminophen, including any adverse event, nausea, dizziness, and somnolence. Serious adverse events were uncommon for all interventions, but studies were not designed to assess risk of overdose, opioid use disorder, or long-term harms. Evidence on how benefits or harms varied in subgroups was lacking. Conclusions. Opioid therapy was associated with decreased or similar effectiveness as an NSAID for some acute pain conditions, but with increased risk of short-term adverse events. Evidence on nonpharmacological therapies was limited, but heat therapy, spinal manipulation, massage, acupuncture, acupressure, a cervical collar, and exercise were effective for specific acute pain conditions. Research is needed to determine the comparative effectiveness of therapies for sickle cell pain, acute neuropathic pain, neck pain, and management of postoperative pain following discharge; effects of therapies for acute pain on non-pain outcomes; effects of therapies on long-term outcomes, including long-term opioid use; and how benefits and harms of therapies vary in subgroups.