Regardless, the reason this study became widely discussed is because the primary outcome of the trial was negative, concluding there was “no evidence that opioids should be prescribed for people with acute non-specific low back or neck pain.” It is worth parsing this statement semantically, noting the authors do not conclude opioids should not be prescribed, only that evidence is lacking in support. In this respect, the conclusion is absolutely true.

Only one other study of reasonable quality informs practice with respect to opiate analgesia for low back pain in the emergency department. Published in JAMA in 2015, the authors conducted a three-arm trial comparing cyclobenzaprine, oxycodone-acetaminophen, and placebo.³ In contrast to the OPAL study, this trial specifically excluded patients whose pain had persisted for more than two weeks. Patients were all prescribed naproxen in addition to the study medication, and were able to take one or two tablets of these immediate-release preparations up to every eight hours, as needed.

The primary outcome was a more relevant seven-day outcome, rather than six-week follow-up. Like OPAL, this was a “negative” trial, in which there was no “statistically significant” difference between functional outcomes between any groups. It is worth noting, however, that the group with the least pain, the greatest improvement, and the fewest days off work was the group taking oxycodone-acetaminophen. A frequentist approach to this trial would conclude, if the trial were to be repeated many times, nearly all the trials would replicate the favorable effects seen for oxycodone-acetaminophen. A Bayesian approach to interpretation would depend on your prior assumptions regarding the efficacy of opiates for treating acutely painful conditions, and may also support the differences favoring oxycodone-acetaminophen, as well.

Finally, even though a seven-day outcome is more relevant, successful acute treatment in emergency medicine may be better measured by time frames of 72 hours or less. In that respect, these trials, particularly OPAL, provide very little insight into whether opiate analgesia supports this early recovery. Only exploratory outcomes provide some supporting evidence that opiate analgesia may improve return to activities and work, but these observations are weak enough they are best represented as equipoise for future research.

After much ado, we may finally arrive back where we started, with little relevant evidence on this specific topic capable of informing our practice in the emergency department. The analgesic options available to us in the emergency department remain limited, as are the options readily prescribed in oral form for discharge. Attempts to discern an advantage associated with skeletal muscle relaxants were unable to find benefit relating to metaxalone, tizanadine, or baclofen.⁴ In a similar fashion, even the addition of acetaminophen, or the addition of diazepam, to a non-steroidal anti-inflammatory did not show an advantage in function or analgesia.^5,6