Muscle relaxants were the most commonly (32%) prescribed medication upon discharge from the ED for lower back pain.
Are they effective?
Muscle relaxants, such as cyclobenzaprine, provide short term pain-relief for patients with acute low back pain compared to placebo.
There is little difference in efficacy among the various muscle relaxants.
Evidence for muscle relaxants for back pain is weak compared to NSAIDs, so limit use to patients who have contraindications to NSAIDS.
There is no strong evidence that combination therapy with NSAIDs is more effective than NSAIDs alone.
If using during the day, consider using a lower dose (cyclobenzaprine 5mg) and a higher dose at night (10mg).
If treating with NSAIDs, consider using only at night to promote sleep.
Also, limit use to those patients who can tolerate the side effect profile of muscle relaxants, which include anticholinergic effects, dizziness, and sedation.
Risks of these agents increase with age, so should be used with caution in older adults.
Often given to this population due to fears of NSAID side effects.
References
Friedman et al., 2019. Annals of Emergency Medicine
A Randomized, Placebo-Controlled Trial of Ibuprofen Plus Metaxalone, Tizanidine, or Baclofen for Acute Low Back Pain.
