LOS ANGELES – Could medical marijuana be an antidote for the nation’s scourge of fatal overdoses caused by prescription pain medication? A new study suggests that the answer is yes, and it has set off a flurry of medical debate over the risks and benefits of making cannabis more widely available to patients.
The new research, published Monday in the journal JAMA Internal Medicine, finds that deaths associated with the use of opiate drugs fell in 13 states after they legalized medical marijuana. Compared with states where there is no formal access to marijuana, those that allowed certain patients legal access to cannabis saw a steady drop in opiate-related overdoses that reached 33 percent, on average, six years after the states’ medical marijuana laws took effect.
“The striking implication is that medical marijuana laws, when implemented, may represent a promising approach for stemming runaway rates of nonintentional opioid-analgesic-related deaths,” opiate-abuse researchers Dr. Mark S. Brown and Marie J. Hayes wrote in a commentary accompanying the study. “If true, this finding upsets the apple cart of conventional wisdom regarding the public health implications of marijuana legalizations and medicinal usefulness.”
That apple cart has already been shaken by a growing body of research suggesting that marijuana’s psychoactive ingredients may enhance the painkilling effects of opiate drugs, allowing patients using marijuana for pain to take lower – and less dangerous – doses of opiate medications.
“It’s so apparent that our patients can decrease, diminish or wean themselves completely off of opiates, and that it improves their quality of life,” said Dr. Donald I. Abrams, a University of California, San Francisco, oncologist who was not involved with the study. In a small study published in 2011, Abrams found that cancer patients taking morphine and oxycodone experienced greater pain relief at lower opiate blood-concentrations when a vaporized form of marijuana was added to their drug regimen. He has just begun recruiting for a study that will explore whether the same formulation can reduce pain, inflammation and opiate doses in patients with sickle-cell disease.
But those who have opposed expanding access to medical marijuana said they were not persuaded that cannabis – a plant designated by the federal Drug Enforcement Administration as having “no recognized medicinal use” – is a safer alternative to opioids. “Clearly the study raised an intriguing hypothesis, but many questions still need to be answered,” the National Institute on Drug Abuse said in a statement released Monday. The analysis “should not be oversimplified,” the statement warned.
The results showed that after a state began to implement a medical marijuana law, the rate of its nonintentional opiate overdose fatalities fell compared with those of states without such laws.
And that comparative decline picked up steam in the first six years after the law went into effect. On average, the analysis showed, states passing medical marijuana laws saw annual reductions of roughly 25 percent in their opioid-related death rates compared to states with no such laws.
Dr. Mark Ware, a pain specialist and professor of family medicine at McGill University in Montreal, called the JAMA Internal Medicine study “very interesting, and methodologically robust.” But, he added, “there’s probably a temptation to extend the findings of this study to far broader conclusions than are justified.”
The United States “is conducting a natural experiment” on a national scale, said Ware, executive director for the Canadian Consortium for the Investigation of Cannabinoids, an advocate for more research on marijuana’s medical potential.