Systemic Pharmacologic Therapies for Low Back Pain: A Systematic Review for an American College of Physicians Clinical Practice Guideline

Background: A 2007 American College of Physicians guideline addressed pharmacologic options for low back pain. New evidence and medications have now become available. Purpose: To review the current evidence on systemic pharmacologic therapies for acute or chronic nonradicular or radicular low back pain. Data Sources: Ovid MEDLINE (January 2008 through November 2016), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and reference lists. Study Selection: Randomized trials that reported pain, function, or harms of systemic medications versus placebo or another intervention. Data Extraction: One investigator abstracted data, and a second verified accuracy; 2 investigators independently assessed study quality. Data Synthesis: The number of trials ranged from 9 (benzodiazepines) to 70 (nonsteroidal anti-inflammatory drugs). New evidence found that acetaminophen was ineffective for acute low back pain, nonsteroidal anti-inflammatory drugs had smaller benefits for chronic low back pain than previously observed, duloxetine was effective for chronic low back pain, and benzodiazepines were ineffective for radiculopathy. For opioids, evidence remains limited to short-term trials showing modest effects for chronic low back pain; trials were not designed to assess serious harms. Skeletal muscle relaxants are effective for short-term pain relief in acute low back pain but caused sedation. Systemic corticosteroids do not seem to be effective. For effective interventions, pain relief was small to moderate and generally short-term; improvements in function were generally smaller. Evidence is insufficient to determine the effects of antiseizure medications. Limitations: Qualitatively synthesized new trials with prior metaanalyses. Only English-language studies were included, many of which had methodological shortcomings. Medications injected for local effects were not addressed. Conclusion: Several systemic medications for low back pain are associated with small to moderate, primarily short-term effects on pain. New evidence suggests that acetaminophen is ineffective for acute low back pain, and duloxetine is associated with modest effects for chronic low back pain.