People who arrived at the emergency department with severe low back pain didn’t experience more relief with muscle relaxants or opioids than with over-the-counter painkillers, in a study published in JAMA.

Nonsteroidal anti-inflammatory drugs (NSAIDs) alone offered as much relief as more powerful painkillers.

This was surprising, lead author Benjamin W. Friedman, MD, MS, of Montefiore Medical Center at Albert Einstein College of Medicine in the Bronx, New York, told Reuters Health by email.

“I think it was generally believed that opioids and skeletal muscle relaxants are useful therapy when combined with NSAIDs for acute low back pain,” Dr. Friedman said.

A quarter of people who come to the ED with low back pain receive NSAIDs and opioids, and another quarter receive NSAIDs and muscle relaxants, while 15 percent receive all three, Dr. Friedman said.

He and his colleagues studied 323 patients who arrived at the ED with low back pain that started within the previous two weeks.

Everyone in the study was instructed to take 500 mg of naproxen twice daily. In addition, the patients were randomly assigned to receive a 10-day course of either a placebo pill, cyclobenzaprine, or oxycodone, to be taken every eight hours while pain persisted.

A week later, and also a month later, patient-reported measures of pain, function, and use of health care resources were all similar regardless of the type of pain medication, the researchers reported in an article online October 20, 2015, in JAMA.

By seven days after the study began, almost two-thirds of patients in each group had improvements in pain level and function, though half reported some persistent functional impairment and more than half were still using medication.

By three months after the ED visit, almost a quarter of the group said they still felt moderate to severe pain requiring medication, but less than 3 percent said they had taken an opioid painkiller in the previous three days.

Some of the medications ED providers rely on don’t appear to do any good, Dr. Friedman said.

“Though the results are perhaps not surprising, combination therapy of this sort is still very common,” Richard A. Deyo,MD, MPH, of Oregon Health and Science University in Portland, who was not part of the new study, told Reuters Health by email.

“This study may encourage more cautious use of opioids and muscle relaxants for acute back pain, resulting in fewer side effects and seemingly no loss of benefit,” Dr. Deyo said.