ANN ARBOR—Patients using medical marijuana to control chronic pain reported a 64 percent reduction in their use of more traditional prescription pain medications known as opioids, a University of Michigan study finds.

The 185 patients from a medical marijuana dispensary in Ann Arbor also reported fewer side effects from their medications and a 45-percent improvement in quality of life since using cannabis to manage pain.

Researchers from the U-M School of Public Health and Medical School said their results suggest that for some people, medical marijuana may be an alternative to more common prescription painkillers at a time when national health leaders are asking the medical community to cut back on prescribing drugs like Vicodin and OxyContin.

“We’re in the midst of an opioid epidemic and we need to figure out what to do about it,” said Kevin Boehnke, lead author of the study and doctoral student in the School of Public Health’s Department of Environmental Health Sciences. “I’m hoping our research continues a conversation of cannabis as a potential alternative for opioids.”

Just last week, the Centers for Disease Control and Prevention issued 12 recommended guidelines for prescribing opioids, saying prescriptions for them have quadrupled since 1999, and that 40 people die every day from an overdose of these drugs.

“We are learning that the higher the dose of opioids people are taking, the higher the risk of death from overdose. This magnitude of reduction in our study is significant enough to affect an individual’s risk of accidental death from overdose,” said study senior author Dr. Daniel Clauw, professor of pain management anesthesiology at the U-M Medical School.

Surveys were conducted from November 2013 to February 2015.

The researchers originally set out to find out if cannabis use was more effective for sufferers with severe centralized chronic pain, for whom the opioids have not always worked well.

“We hypothesized that cannabis might be particularly effective for the type of pain seen in conditions such as fibromyalgia, since there are many studies suggesting that synthetic cannabinoids work in these conditions,” Clauw said. “We did not see this because the patients in this study rated cannabis to be equally effective for those with different pain severity.”

It was the patients with less severe chronic pain who reported better quality of life and less use of opioids.

“We would caution against rushing to change current clinical practice towards cannabis, but note that this study suggests that cannabis is an effective pain medication and agent to prevent opioid overuse,” Boehnke said.

At present, 23 states and the District of Columbia have legalized cannabis for medical purposes and four states allow it for recreational use.

The researchers said population level research has shown a reduction in opioid use in states where medical cannabis is legal, but the U-M study is one of the first to look at individual patterns of use. A study also released this month from Israel followed people for six months and found a 44-percent reduction in opioid use.

The researchers said one limitation of their study, however, is that it was conducted with people at a dispensary who are presumed to be believers in the medical benefits of marijuana. These participants were surveyed after they had been using marijuana, which may decrease the accuracy of their recollections. The team plans to continue research with this population but also conduct studies with patients who have not yet tried marijuana for pain management.

Dr. Evangelos Litinas of Ann Arbor also was a member of the research team.

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