ACR 2011: The Debate Over Medical Marijuana Continues

Although there is some evidence showing treatment with medical marijuana can benefit patients with arthritis, chronic pain, and other conditions, there are also serious concerns over quality control, non-standardized dosing, and other potential safety risks.

The light-hearted debate between Stuart Silverman, MD, and Arthur Kavanaugh, MD, during the “Joints for Joints: Medical Marijuana is Useful for Treating Rheumatic Disease” session at the 2011 ACR/ARHP Annual Meeting, which featured music clips, humorous Photoshopped images of the presenters, and plenty of marijuana-focused quips and double entendres, also covered several serious issues associated with the proliferation in use of medical marijuana for treating rheumatic diseases and a range of chronic painful conditions.

Silverman, who is clinical professor of medicine at University of California, Los Angeles, and the medical director of OMC Clinical Research Center, argued against the position that medical marijuana is an useful treatment, pointing out that although there is some research showing some clinical benefits, they are outweighed by the risks associated with medical marijuana and the lack of solid information available for physicians and patients. “If we’re going to prescribe it, we need to know what it is, and how it works,” he said.

In addition to noting the lack of guidelines for physicians who recommend medical marijuana and the variability in practice, Silverman said that the biggest problem with medical marijuana is that, most of the time, physicians and patients don’t know what they’re getting from the dispensaries. He showed the audience several examples of the ads and menus of products offered by dispensaries in California, most of which had given silly, euphemistic names to the marijuana strains (“Green Dream,” “Orange Kush,” “AK47,” etc) that provided no useful information. “How do the clinics know the potency of what they’re offering? How do they check the THC content? These product names are just marketing gimmicks,” he said.

Testing has shown that there is a tremendous amount of lot variability in medical marijuana, along with frequent mold and fungus contamination, wide variability in THC content, lack of transparency from suppliers, and other variables that together make it difficult for patients and physicians to make informed prescribing decisions. Silverman said that often, patients rely on the product recommendations from the dispensaries and collectives selling the products, Most patients do not know about species differences, or about the risk of contamination.

The variable methods of medical marijuana delivery also introduce a large degree of uncertainty, making accurate dosing a challenge. For example, Silverman noted that edible marijuana products contain variable levels of active ingredient, and are absorbed into the system much slower than inhaling. Smoking (whether via pipe, joint, or inhaler) remains the most common and easiest route of delivery for medical marijuana, with vaporizers being the preferred delivery method for many patients. But the actual amount of active ingredient delivered is highly variable, based on smoking style. Smoking, of course, carries with it its own additional health risks; smoke from a joint or pipe contains the same constituents (apart from nicotine) as cigarette smoke. Plus, Silverman observed that “smoking results in rapid onset of effect, but with high serum levels of the active ingredient over short intervals, which is not good for treating chronic pain.”

Medical marijuana has a wide range of side effects, with a highly variable incidence. In order to prescribe this medically, physicians must determine if its therapeutic effects outweigh the potential harmful side effects. Silverman concluded that although medical marijuana might have some potential benefits, it is “not ready for primetime” until serious issues regarding dosing standardization, quality control, potential adverse effects, addiction and dependence prevention, and provider training are addressed.

Arthur Kavanaugh, MD, professor of medicine, division of rheumatology, allergy, immunology, University of California, San Diego, arguing the “pro” position in this debate, offered several examples of studies showing the benefits of medical marijuana for treating musculoskeletal pain and other rheumatic conditions. He also said that there is some strong in vitro evidence for the anti-inflammatory effects of marijuana. Kavanaugh was more sanguine about the safety and efficacy issues associated with medical marijuana, noting that we have a mountain of anecdotal evidence from thousands of years of medicinal and recreational use. He did agree with Silverman that it is vitally important to work to reduce the variability in active ingredient strength among the products and to improve patient and provider education. He speculated that these deficiencies may be due in large part to the degree to which politics in the US has hindered development and testing of medical marijuana.

This activity is not sanctioned by, nor a part of, the American College of Rheumatology.