By “The studies that we had out there were short-term studies and mostly compared opioids to placebo medications,” Krebs said. “From those studies, we knew that opioids can improve pain a little bit more than a placebo, or sugar pill, in the short term, but that’s all we knew.”
But that’s changing. Krebs is the lead author of a new study that looks at the effectiveness of opioids for treating chronic pain over 12 months published Tuesday in the Journal of the American Medical Association.
The study involved 240 veterans with chronic back pain or osteoarthritis of the knee or hip who had pain that was ongoing and intense. Half were treated with opioids and half with non-opioid medications — either common over-the-counter drugs like acetaminophen or naproxen, or prescription drugs like topical lidocaine or meloxicam. Doctors and patients knew what group they were in, said Krebs, and that was deliberate because people’s expectations can influence how they feel.
“We found at the beginning of the study that patients who were enrolled really thought that opioids were far more effective than non-opioid medications,” she said.
But after as little as six months, the non-opioid group reported their pain was slightly less severe than the opioid group’s collective assessment. By the end of the year, Krebs said, “there was really no difference between the groups in terms of pain interference with activities. And over time, the non-opioid group had less pain intensity, and the opioid group had more side effects,” such as constipation, fatigue and nausea.
The study didn’t explore why, but Krebs has a theory: opioid tolerance.
“Within a few weeks or months of taking an opioid on a daily basis, your body gets used to that level of opioid, and you need more and more to get the same level of effect,” she said.
