Canada's Marijuana Regulations Raise Efficacy, Safety Issues

Canada’s road toward government-sanctioned and expanded medical marijuana access is paved with good intentions but obstructed by everything from faulty science to potentially lethal consequences for patients, according to many in that country’s health care community. Government officials proposed regulations on April 6 that expand patient access to marijuana for those who are unable to find relief from pain, nausea, loss of appetite, and other serious symptoms using conventional therapies and who have physician approval (see sidebar, next page). But Canadian cancer experts along with other health professionals and patient advocates question marijuana’s therapeutic safety and efficacy when used with conventional medications as well as its proper dosage, purity, and cost. Some also feel the Canadian health bureaucracy is forcing all physicians into the uncomfortable role of “gatekeeping” access to marijuana without specifying their qualifications or training. “There is skepticism that this is going to be the panacea we’re led to believe by lay advocates,” cautions Neil Hagen, M.D., head of the Cancer Pain Clinic at Calgary’s Tom Baker Cancer Center and director of the Division of Palliative Medicine at the University of Calgary. “Palliative care patients often have to take several different kinds of medications, including opiates. When one adds to that a psychoactive drug like smoked marijuana there is a risk of toxicity. The majority of cancer patients who take antinausea medications can also have quite severe side effects such as hallucinations,” Hagen cautioned. According to Hagen, crude smoked marijuana delivers a variety of carcinogens and can have toxic synergistic reactions with some common cancer drugs. In addition, marijuana appears to be a poor substitute for conventional medications, and supplies can vary considerably in both potency and purity, he said. Critics of medical marijuana argue that Marinol, an oral prescription drug containing marijuana’s principal active ingredient, delta-9-tetrahydrocannabinol (THC), has been available since 1985. But proponents contend that the effects of Marinol and other oral delivery systems are compromised by variable gastrointestinal absorption. Smoking, they argue, remains the best way to experience marijuana. Hagen, however, sees this as simply a “smokescreen.” “There is even more skepticism about the strong lobbying in support of medical marijuana because of where it comes from—folks involved in other aspects of the marijuana legalization movement,” Hagen added. “We’re concerned that there is too much attention focused on marijuana when there are so many other cancer pain control needs.” Catherine Lappe, a senior adviser to Canada’s Health Minister Allan Rock, however, disagrees. “This is separate from the debate on decriminalization or legalization. Heroin derivatives and morphine have been used for years, and there’s no connection between controlled use and general legalization,” she said. But Peter Barrett, M.D., a urologist and president of the Canadian Medical Association, thinks that the issue of inadequate pain management has been capitalized on by those supporting marijuana legalization and used to influence overall public opinion. “There is no question that we can do better in terms of palliative care,” Barrett said. “The problem we have with this is that there aren’t any good evidence-based studies out there validating marijuana as a valid therapeutic and at the same time there are groups out there that simply want recreational access. Physicians aren’t going to be comfortable recommending an unproven, addictive substance that has a number of known risks and no known value.” In addition, even though pharmaceutical advances have actually enhanced pain control efforts, the sense among many patients that cancer-associated pain is uncontrollable persists and can be exploited, according to Hartley Stern, M.D., president of the Canadian Oncology Society and chief executive officer of the Ottawa Regional Cancer Center. “In terms of pain management, we are light years ahead of where we were even 5 years ago, but if in fact there is some benefit to patients from marijuana, no one in the cancer community would object to providing it. However, at the same time I’m not hearing a groundswell of demand for it from cancer patients,” Stern said. According to Jeff Poston, Ph.D., executive director of the Canadian Pharmacists Association, the proliferation of unregulated herbs and “natural” health products has helped to create unrealistic expectations among the lay public that these substances must necessarily be safe and effective. “There is this general attitude that somehow the medical establishment is creating barriers to cheap and effective natural products and medical marijuana is an extension of that. It’s a cultural mind-set in which this debate over medical marijuana is taking place,” Poston said. “When it comes to marijuana, there is plenty of ‘experience’ out there, but the problem is that virtually none of it comes from scientifically based clinical trials.” Meanwhile, Canada’s oldest and largest patient advocacy group, the Canadian Cancer Society, is taking a cautious approach, evaluating the scientific literature and awaiting the results of clinical trials being administered by the country’s federal public health agency Health Canada, said Barbara Whylie, M.B., director of medical affairs and cancer control for the CCS and the National Cancer Institute of Canada. Ironically, Canada’s proposed rules were released less than 10 days after the U.S. Supreme Court heard oral arguments in a case pitting the Justice Department against an Oakland, Calif.-based “cannabis club”—a buyer’s cooperative supplying marijuana to those providing evidence from a physician that it is “medically necessary.” A ruling is expected in June. In a 1996 state referendum, California voters approved a proposition that allows the distribution of marijuana to those with a physician’s recommendation. In addition, since 1976, voters in Alaska, Arizona, Colorado, the District of Columbia, Hawaii, Maine, Nevada, Oregon, and Washington have approved ballot measures supporting the use of marijuana for medical purposes. Meanwhile, 26 state legislatures and numerous localities have recognized and/or authorized marijuana use for medical purposes or decriminalized it. Nevertheless, manufacturing, distributing, or using marijuana for any purpose remains illegal in the United States under federal law. And even though Canada’s marijuana regulations do not specifically bar American patients who sometimes travel to Canada to purchase less expensive pharmaceuticals regulated by Canadian government price controls, the application process and regular medical monitoring would make access difficult if not impossible, according to Health Canada spokesperson Roslyn Tremblay. Dr. Peter Barrett

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