What Is the Role of Muscle Relaxants or Opiates in the Treatment of Acute Non-Traumatic LBP?

Background: Acute, non-traumatic low back pain (LBP) is a common chief complaint and has been estimated to lead to more than 2.7 million ED visits annually nationwide. It affects a broad range of individuals and can be painful and debilitating long after an initial ED visit. Often times in clinical practice, evidence based decisions on medical management of acute lower back pain seem to be thrown out the window; rather medications are prescribed on a gestalt medicament do jour. NSAIDs, muscle relaxants, and opioids have all been used in isolation and in combination for treating acute LBP but trials investigating the efficacy of these medications combined have produced heterogeneous results.

Clinical Question: Does combining either muscle relaxants or opioids to a regimen of NSAIDs improve functional outcomes and pain in patients with acute LBP?


Freidman BW, et al. Naproxen with Cyclobenzaprine, Oxycodone/Acetaminophen, or Placebo for Treating Acute Lower Back Pain: A Randomized Clinical Trial. JAMA. 2015; 314(15): 1572-1580. 26501533

Population: Adults aged 21-64 presenting to an urban ED with acute, non-traumatic, non-radicular, functionally impairing LBP.

Intervention: Naproxen plus cyclobenzaprine or naproxen plus oxycodone/acetaminophen (APAP).

Control: Naproxen plus placebo.

Outcome (Primary): Improvement in RMDQ (tool used to measure LBP and functional impairment) between ED discharge and one week later.

  • RMDQ Score ranges from minimum of 0 to maximum of 24
  • A 5 point improvement on this scale is considered clinically significant

Outcome (Secondary): Actual RMDQ scores at 1-week and 3-month follow up, adverse events, as well as specific exploratory outcomes as specified below:

One week after discharge from ED:

  • Participants’ worst back pain level in the previous 24 hours
  • Frequency of analgesic use in the previous 24 hours
  • Satisfaction with treatment
  • Day in which participant returned to work
  • Frequency of visits to any clinician

Three months after discharge from ED:

  • Participants’ worst back pain level in the previous 72 hours
  • Frequency of LBP in the previous 72 hours
  • Frequency of opioid use

Design: Double-blinded, 3-group randomized clinical trial.


  • Radial pain (below the gluteal folds)
  • Traumatic pain
  • Pain >2 weeks in duration
  • Hx > 1 episode of LBP per month
  • Pregnant or lactating
  • Unavailable for follow-up
  • Allergy/contraindication to meds
  • Chronic opioid use currently or in past

Primary Results

  • 323 patients included in the study at one urban ED
  • All 3 study groups with similar demographics
  • Baseline median RMDQ scores:
    • Placebo 20
    • Cyclobenzaprine 19
    • Oxycodone/APAP 20
  • Mean RMDQ improvement at 1 week:
    • Placebo 9.9
    • Cyclobenzaprine 10.1
    • Oxycodone/APAP 11.1
  • Between-group difference in mean RMDQ score improvement:
    • Cyclobenzaprine vs placebo: 0.3 (p=.77)
    • Oxycodone/APAP vs placebo: 1.3 (p=.28)
    • Oxycodone/APAP vs cyclobenzaprine : 0.9 (p=.45)

Secondary Results

  • Adverse effects more likely in oxycodone/APAP group (number need to harm 5.3) than to placebo (number need to harm 7.8)

Critical Findings: No improvement in pain or functional outcomes when adding cyclobenzaprine or oxycodone/APAP to naproxen at 1-week follow-up.


  • Double-blinded RCT
  • Greater than 90% follow up in all groups
  • Clear clinical question that is often encountered in the ED setting
  • Results consistent with other reports of outcomes with acute LBP
  • Patients had ability to titrate the investigational medication in question, mimicking real clinical practice and minimizing adverse effects


  • Only one ED included in the study
  • Primary outcome measure was subjective – increases chance of bias
  • Large number of exclusion criteria
  • Limited generalizability as patients were not asked about current NSAID use at time of enrollment
  • Compliance with regimen randomized to was low (though this mimics real life)
  • The authors do not discuss what medications the study participants were given in the ED prior to discharge

Authors Conclusions: “Among patients with acute, non-traumatic, non-radicular LBP presenting to an ED, adding cyclobenzaprine or oxycodone/acetaminophen to naproxen alone did not improve functional outcomes or pain at 7 days. These findings do not support the use of these additional medications in this setting.”

Our Conclusions: Naproxen monotherapy is sufficient for medical management of acute non-traumatic, non-radicular LBP. Adding cyclobenzaprine or oxycodone/APAP was not shown to have any benefit in pain or functional outcomes both short and long term. Patients may in fact have more adverse outcomes from adding these medications to the mix. Keep in mind the individual patient’s current medication regimen, as this study did not look at outcomes for patients already on NSAIDs at the time of enrollment.

Potential to Impact Current Practice: In the right patient this can be brought to clinical practice immediately, leading to less polypharmacy and less adverse medication effects.

Bottom Line: Addition of either cyclobenzaprine or oxycodone/APAP to naproxen did not improve pain or functional outcomes in patients with acute LBP.

Guest Post By:

IMG_0125Aaron Arredondo, MD
PGY4 Resident
NYU/Bellevue EM Residency Program

Peer Reviewed By: Salim Rezaie (Twitter: @srrezaie)

Cite this article as: Anand Swaminathan, "What Is the Role of Muscle Relaxants or Opiates in the Treatment of Acute Non-Traumatic LBP?", REBEL EM blog, December 7, 2015. Available at: https://rebelem.com/what-is-the-role-of-muscle-relaxants-or-opiates-in-the-treatment-of-acute-non-traumatic-lbp/.

Like this article?

Share on Facebook
Share on Twitter
Share on Linkdin
Share via Email

Want to support rebelem?