Muscle relaxant or opioid combined with naproxen does not improve low back pain, says new study


According to a study in the Journal of the American Medicine Association (JAMA), patients with acute low back pain (LBP) achieved no greater pain relief of improvement in functional outcomes when treated with the non-steroidal anti-inflammatory drug, naproxen, combined either a muscle relaxant (acetaminophen) or opioid (oxycodone), than with naproxen combined with a placebo (cyclobenzaprine).

Benjamin W. Friedman, of the Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, USA, and colleagues found that neither naproxen combined with oxycodone or acetaminophen, nor naproxen combined with cyclobenzaprine provided better pain relief or better improvement in functional outcomes than naproxen combined with placebo. Measures of pain, functional impairment, and use of healthcare resources were not different between the study groups at 7 days or at 3 months after the emergency department visit.

The study randomly assigned 323 patients who presented to an emergency department with non-traumatic, non-radicular LBP of two weeks’ duration or less to receive a 10-day course of naproxen+placebo (n = 107); naproxen+cyclobenzaprine (5mg) (n = 108); or naproxen+oxycodone, 5mg/acetaminophen, 325mg (n = 108). Participants were instructed to take one or two of these tablets every eight hours, as needed for LBP. naproxen, 500 mg, was to be taken twice a day. Patients also received a standardised 10-minute LBP educational session prior to discharge.

Regardless of allocation, nearly two-thirds of patients demonstrated clinically significant improvement in LBP and function one week later. However, 40% of the cohort reported moderate or severe pain, half reported functionally impairing LBP, and nearly 60% were still using medication for their LBP one week later. By a three-month follow-up, nearly a quarter of the cohort reported moderate or severe pain and use of medications for LBP. Three months after the emergency department visit, regardless of study group, opioid use for LBP was uncommon, with fewer than 3% of patients reporting use of an opioid within the previous 72 hours.

“These findings do not support the use of these additional medications in this setting,” the authors write.