Naproxen + placebo was as good as (possibly better than) naproxen plus orphenadrine or naproxen plus methocarbamol for acute low back pain.
Why does this matter?
There is conflicting evidence about muscle relaxers for acute back pain. Diazepam was recently shown to make it worse. A systematic review showed possible benefit of cyclobenzaprine. In an era of rampant opiate abuse, agents that are not habit forming but may help patients would be welcome. So do the muscle relaxers orphenadrine and methocarbamol help when added to naproxen?
I feel so relaxed
This was a RCT of 240 patients with acute low back pain all receiving naproxen plus either placebo, orphenadrine, or methocarbamol. Groups were well matched. The primary outcome was improvement on a validated disability score at one week. They found that the naproxen + placebo group had the biggest improvement, though there was no statistical superiority over the two groups that got a muscle relaxer. Adverse effects were similar among all three groups. These two muscle relaxers did not appear to offer any clinically meaningful improvement in short term disability for acute low back pain.
A Randomized, Double-Blind, Placebo-Controlled Trial of Naproxen With or Without Orphenadrine or Methocarbamol for Acute Low Back Pain. Ann Emerg Med. 2017 Oct 28. pii: S0196-0644(17)31700-6. doi: 10.1016/j.annemergmed.2017.09.031. [Epub ahead of print]
Peer reviewed by Thomas Davis, MD.