Cyclobenzaprine does not help!

By Michael Barrie, OSU EM Assistant Professor

A great emergency medicine study in this month’s JAMA: Friedman et. al Naproxen with cyclobenzaprine, oxycodone/acetaminophen, or placebo for treating acute low back pain: A randomized clinical trial.” This was a randomized, double-blind controlled trial to see if adding narcotics or cyclobenzaprine to naprosyn helps improve symptoms in patients with lumbar back pain compared to those that received naprosyn plus placebo. They showed there was NO benefit.

Conclusions and Relevance  Among patients with acute, nontraumatic, nonradicular LBP presenting to the ED, adding cyclobenzaprine or oxycodone/acetaminophen to naproxen alone did not improve functional outcomes or pain at 1-week follow-up. These findings do not support use of these additional medications in this setting.

I think these results are consistent with my experience as an emergency physician. Lumbar back pain is a terrible disease. It can be very debilitating and is frustrating for patients because we generally do little workup if the patient has no red flags for more serious etiologies such as cauda equina, epidural abscess, AAA, spinal fracture, to name a few. And the most frustrating aspect of managing lumbar back pain is that we seem to only have one effective treatment– TIME.

This paper has limitations. The most important limitation is they excluded all patients with radicular symptoms.

Patients were excluded for radicular pain, which we defined as pain radiating below the gluteal folds, direct trauma to the back within the previous month, pain duration for more than 2 weeks, or recent history of greater than 1 LBP episode per month. We also excluded patients who were pregnant or lactating, unavailable for follow-up, with allergy or contraindication to the investigational medications, or had chronic opioid use currently or in the past. Patients could only be enrolled once.

Excluding radicular pain may have been an attempt to screen out patients with potentially more serious etiologies of pain, however I think it is unfortunate because it then leads us to wonder if these adjuncts could benefit patients with radicular symptoms. Also realize that patients with traumatic lumbar back pain should have a lower threshold for imaging to exclude fracture or dislocation. However, I disagree with those that argue traumatic causes of back pain warrant muscle relaxers, as I doubt a pharmacological approach to treating muscle spasm would show any benefit over placebo + NSAIDs.

Dr. Pallin of NEJM Journal watch also reviewed this article, and points out that cyclobenaprine is a tricyclic antidepressant (TCA) with many potential side effects including lethal overdose, with very scant evidence that it benefits any patients.

This article is a great reminder that for those patient’s with lumbar back pain, adding additional therapies such as cyclobenzaprine likely only adds risk of side effects and has little potential benefit. Unfortunately, I personally find it difficult to give patients nothing and worry about my satisfaction numbers, so many times I do choose to give muscle relaxants such as valium, steroids and narcotic pain medications. Hopefully this article and others to come will help guide my practice away from potentially ineffective therapies.

References

  1. Friedman BW et al. Naproxen with cyclobenzaprine, oxycodone/acetaminophen, or placebo for treating acute low back pain: A randomized clinical trial. JAMA 2015 Oct 20; 314:1572. (http://dx.doi.org/10.1001/jama.2015.13043) – See more at: http://www.jwatch.org/na39384/2015/10/20/avoid-sedatives-and-opioids-treating-low-back-pain#sthash.YQYsOtLx.dpuf
  2. http://www.jwatch.org/na39384/2015/10/20/avoid-sedatives-and-opioids-treating-low-back-pain
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