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?


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


Naproxen (500 mg BID) plus cyclobenzaprine (5 mg PRN Q8) or naproxen plus oxycodone/acetaminophen (325mg/5mg PO Q8).


Naproxen as above plus placebo (PRN Q8).


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


Randomized, double-blind, placebo controlled, three arm 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

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

Additional Results

  • 323 patients included in the study at one urban ED
  • All 3 study groups with similar demographics
  • Adverse effects more likely in oxycodone/APAP group (number need to harm 5.3) than to placebo (number need to harm 7.8)
  • 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)


  • 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

Author's 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 Impact To 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.