By Pat Anson, Editor

As more and more states legalize medical marijuana, many chronic pain patients are turning to cannabis for pain relief. Some are also continuing to use opioid pain medication – raising concern that the combination could increase their risk of substance abuse.

But a new study at the University of Michigan found that patients who use marijuana and opioids are not at higher risk for alcohol and drug abuse. Researchers studied 273 patients at a marijuana clinic in Michigan and found that more than 60% were also using prescription opioids.

"We expected that persons receiving both cannabis and prescription opioids would have greater levels of involvement with alcohol and other drugs," said Brian Perron, PhD, of the School of Social Work at the University of Michigan.

"However, that wasn't the case -- although persons who were receiving both medical cannabis and prescription opioids reported higher levels of pain, they showed very few differences in their use of alcohol and other drugs compared to those receiving medical cannabis only."

Participants in the study, which is being published in the Journal of Studies on Alcohol and Drugs, did report higher rates of drug use than the general population. But their use of other drugs -- including alcohol, cocaine, sedatives, heroin, and amphetamines – was similar whether they used opioids or not.

“I am thrilled this research is now happening so others will also gain the confidence in trying medical marijuana,” said Ellen Lenox Smith, a medical marijuana advocate and columnist for Pain News Network.

“People who have addictive personalities will have issues weather it is alcohol, marijuana, smoking, or opioids. Those of us without that tendency do not have to be concerned. We have patients that have been using both medications successfully, but most of them have eventually chosen to wean away from the opioids due to the annoying side effects. But while using both, they have seemed to cope fine and metabolize both.”

A noted medical marijuana researcher says cannabis may actually make opioids more effective – enabling some patients to take lower doses.

“We’ve seen it in patients who started using cannabis successfully and they were able to reduce their other medications,” said Mark Ware, MD, an associate professor in Family Medicine and Anesthesia at McGill University in Montreal.

“In some cases they find that the dose of opioids that they were taking, they can lower it and get a similar effect at much lower doses. In others, they don’t need the opioids any longer and they’re able to taper off and stop it completely.”

Ware and other researchers believe medical marijuana may be a safer alternative to opioids, which have a higher risk of addiction and overdose. But they stress that communication between doctors and patients is important – since some doctors may have no idea if a patient is using marijuana.

"Physicians do not actually 'prescribe' medical cannabis -- they only certify whether the patient has a qualifying condition, which allows the patient to gain access to medical cannabis,” said Perron.

“The system of dispensing medical cannabis is completely separate from prescription medications, so physicians may not know whether a given patient is using medical cannabis, how much, and in what form."