By Pat Anson, Editor

A new study has found that use of opioid pain medication declines dramatically when chronic pain patients use medical marijuana.

The small study by researchers at the University of Michigan involved 185 pain patients at a medical marijuana dispensary in Ann Arbor, who were surveyed in an online questionnaire about their use of marijuana and pain medications.

Nearly two-thirds (64%) reported a reduction in their use of prescription pain medications and almost half (45%) said cannabis improved their quality of life. Patients also had fewer side effects from marijuana than they did from opioids.

"We're in the midst of an opioid epidemic and we need to figure out what to do about it," said lead author Kevin Boehnke, a 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."

Last week the Centers for Disease Control and Prevention issued new guidelines that recommend non-pharmalogical therapy and non-opioid drugs for chronic pain. The guidelines do not endorse medical marijuana as a pain treatment, but they do discourage doctors from testing patients for marijuana and from dropping them from their practices if marijuana is detected.

Currently, 23 states and the District of Columbia have legalized marijuana for medical purposes and four states allow it for recreational use.

The University of Michigan researchers found that patients with less severe chronic pain were more likely to report less use of opioids and a better quality of life.

"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.

Researchers said their findings, published in the Journal of Pain, also suggest that overdose death rates would decline dramatically if marijuana was used more widely for pain relief.

“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 senior study author Daniel Clauw, MD, a professor of pain management anesthesiology at the U-M Medical School.

Previous research has found that opioid overdose rates declined by nearly 25 percent in states where medical marijuana was legalized. Another recent study of cannabis use by pain patients in Israel found a 44% reduction in opioid use.

One limitation of the current study is that it was conducted with people at a marijuana dispensary, who are more likely to already be believers in the medical benefits of marijuana.