NEWS: Cannabinoid Treatment for Pain Control Still Marked by Dearth of Research, Legal Constraints

Can cannabis overcome the controversy that surrounds it and enter the mainstream in both research and clinical practice for pain control?

The answer is a qualified yes—because federal policy remains equivocal toward the legality of any use of cannabis, even as more and more states authorize its use for management of pain and many other medical conditions.

In a review published in late 2009 in the Journal of Opioid Management, Minnesota researchers presented a comprehensive case for the analgesic potential of cannabinoids (2009;5-6:341-356). Starting with an overview of the mechanism of action of the compounds, the trio—Kalpna Gupta, MD, her husband Pankaj Gupta, MD, and Jaseena Elikottil, MBBS, of the University of Minnesota in Minneapolis—cite study after study supporting the ability of cannabinoids to combat pain from conditions ranging from cancer to sickle cell disease.

A recent editorial in American Family Physician by James MacDonald, MD, summarized the push toward wider authorization of marijuana for medical use (2009;80:779). Dr. MacDonald noted that the American Academy of Family Physicians supports the use of marijuana under medical supervision and control for specific medical indications. This is farther than other organizations, including the American Pain Society, have been willing to go, he said.

What Does the Evidence Say?

Neither Dr. MacDonald nor Dr. Kalpna Gupta said marijuana and cannabinoids are a panacea for all forms of pain. Nor do they deny there are significant potential side effects from the drugs, including the well-known effects on motor activity and cognition.

They do assert, however, that these agents show great promise for alleviating suffering and can help fill the gaps in treatment, such as situations in which medications like opioids are not effective or cause overwhelming side effects.

In their review, the researchers list the animal-based evidence for the efficacy of cannabinoids in treating neuropathic pain, inflammatory pain and cancer pain. A few small clinical studies have examined the use of cannabinoids to treat various types of pain, some with promising results and others with equivocal findings. However, equivocal results should not be a reason to discontinue this important area of research, the researchers said.

“Currently, there is intriguing evidence from animal studies showing the efficacy of cannabinoids as antinociceptive agents,” they wrote. “However, data from human studies is still emerging. Cannabinoids may form a useful adjunct to current analgesic drugs in many conditions.”

What Are Legislatures Saying?

Dr. MacDonald noted that during the administration of George W. Bush, the Drug Enforcement Administration (DEA) raided dispensaries for medical marijuana and threatened physicians who prescribed it with revocation of their DEA licensure. He observed that the Obama administration has a more “hands-off” attitude toward the issue. Despite this, marijuana remains a Schedule I controlled substance under the federal Controlled Substances Act, whereas 13 states to date have authorized the use of medical marijuana. The indications approved in most states for medical marijuana include cancer, chronic pain, epilepsy and multiple sclerosis—conditions for which other treatments often fail to be an all-encompassing solution.

California was the first out of the gate, and hence, medical marijuana prescription is well established there. Dr. MacDonald said that most physicians in California have written only a handful of recommendations to patients for the use of medical marijuana. However, a small number have made it their business to focus on selling these recommendations, rather than on maintaining an overall high standard of care for their patients, said Dr. MacDonald. This is what spurred him to write his editorial.

“I believe that if more physicians understood the matter, and understood that it [marijuana/cannabinoids] is a valid treatment for many conditions, then in turn more patients would feel comfortable discussing the issue and receiving the recommendation from their own doctors—rather than from these ‘cannabis specialists.’”

What Should Happen Next?

Dr. MacDonald pointed out how “Orwellian” the situation has become, thanks to the past emphasis on criminalizing drug use, and how easily it could be made congruent with reality.

“It is indeed strange for a physician to participate in something that, though legal in the state of California, for instance, is still officially prohibited by the federal government,” Dr. MacDonald wrote in an e-mail from New Zealand, where he is working temporarily at the Otago Health Centre, in Dunedin. “I believe marijuana should be reclassified as a Schedule II substance, allowing open research to take place. And states should be empowered to allow experimentation with the medical marijuana issue.”

Dr. Gupta agreed with the need to conduct carefully designed clinical studies, and to uniformly legalize the medical use of selected cannabinoid medications throughout the country.

“These initiatives should be moved forward quickly because, other than opioids, cannabinoids are the only drugs that are effective for treating severe pain,” she said. “They may be invaluable in cases where opioids stop working, which happens quite frequently due to the induction of tolerance.”

Source: Anesthesiology News