Use of opioids for patients with chronic, non-cancer pain may help, but not a lot.

In a study published by the Journal of the American Medical Association (JAMA), McMaster University researchers reviewed 96 clinical trials with more than 26,000 participants and found opioids provide only small improvements in pain, physical functioning, and sleep quality compared to a placebo.

The opioids, however, also increase the risk of vomiting, drowsiness, constipation, dizziness, nausea, dry mouth, and itching.

The researchers’ analysis also found low to moderate quality evidence showing similar benefits for pain and physical functioning between opioids and non-opioid alternatives such as nonsteroidal anti-inflammatories, antidepressants, and synthetic cannabinoids.

“Despite widespread use, there is not enough known about the benefits and harms of opioids for chronic non-cancer pain,” says Jason Busse, DC, PhD, lead author of the study and a researcher with the Michael G. DeGroote Institute for Pain Research and Care at McMaster University, in a release.

“We found that, compared to a placebo, 12% more patients treated with opioids will experience pain relief, 8% more will notice an improvement in their physical functioning, and about 6% more will find improvement in their sleep quality.

“These are very modest effects, and opioids were not associated with any important improvement in social, role, or emotional functioning,” says Busse, who is also an associate professor of anesthesia at McMaster.

“In addition to the side effects we found can result from opioid use, these medications are associated with addiction, overdose, and death. Given their risks, modest benefits, and the comparable effectiveness of alternatives, our results support that opioids should not be firstline therapy for chronic non-cancer pain.”

The research was funded by the Canadian Institutes of Health Research and Health Canada.