From The MS Information Sourcebook, produced by the National MS Society.
The question of whether marijuana (Cannabis sativa) should be used for symptom management in MS is a complex one. It is generally agreed that better therapies are needed for distressing symptoms-including pain, tremor, and spasticity-that may not be sufficiently relieved by available treatments. Yet there are serious uncertainties about the benefits of marijuana relative to its side effects. The fact that marijuana is an illegal drug in many states and by federal statute (see In the News below) further complicates the issue.
Some people with MS report that smoking marijuana relieves several of their MS symptoms. However, in order for any therapy to be recognized as an effective treatment, this kind of subjective, anecdotal reporting needs to be supported by carefully-gathered, objective evidence of safety and benefit. Unfortunately, it has proven difficult to do carefully controlled clinical trials of marijuana. One reason for this is that marijuana is psychoactive and tends to make people feel "high." This means that people taking the active drug during a clinical trial usually become aware of it-thus "unblinding" the study and possibly biasing results. Studies completed thus far have not provided convincing evidence that marijuana or its derivatives provide substantiated benefits for symptoms of MS.
Conflicting results of previous research, coupled with the need for additional therapies to treat symptoms of MS, make it important that more research be done on the potential of marijuana and its derivatives. The National MS Society is funding a well-controlled study on the effectiveness of different forms of marijuana to treat spasticity in MS, and has established a task force to examine the use of Cannabis in MS to review what is currently known about its potential. This task force will make specific recommendations on the research that still needs to be done to answer pressing questions about the potential effectiveness and safety of marijuana and its derivatives in treating MS.
Early Studies Showed Mixed Results and Some Side Effects
Early studies explored the role of THC (an active ingredient in marijuana-tetrahydrocannabinol) or smoked marijuana in treating spasticity, tremor, and balance control in small numbers of people with MS. Most of these studies were done with THC. Because THC can be given by mouth, it is easier to control the dose. The results of these studies were mixed, and participants reported a variety of uncomfortable side effects. In addition, smoked marijuana poses health risks that are at least as significant as those associated with tobacco.
National Academy of Sciences/ Institute of Medicine Report
Study on Marijuana Derivatives in Mice
More Research Required
In the News
Sativex approved: In April 2005, Health Canada, the drug regulatory agency for Canada , approved the use of the cannabis-derived drug Sativex® (GW Pharmaceuticals) to treat MS-related pain. The approval was based on a small, four-week clinical trial conducted in the United Kingdom in 66 people with MS, the results of which were published in 2005 (Rog DJ et al. Neurology 2005;65:812-819). Sativex contains extracts from the marijuana plant and is administered as a spray into the mouth. This drug is not approved in the United States. In response to a request by the Committee on Safety of Medicines, an advisory body to the Canadian regulatory authority, GW Pharmaceuticals is now conducting a clinical trial to evaluate Sativex as a treatment for spasticity.
Supreme Court Ruling: On June 6, 2005, the Supreme Court ruled that the federal government has the power to prohibit and prosecute the possession and use of marijuana for medical purposes, even in the 11 eleven states (Alaska, Arizona, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont, and Washington) that currently permit it. The decision overturned a 2003 ruling by a federal appeals court that shielded California's Compassionate Use Act, the medical-marijuana initiative adopted by the state's voters nine years ago, from federal drug enforcement. The appeals court had held that Congress lacked constitutional authority to regulate the noncommercial cultivation and use of marijuana that did not cross state lines. The current decision reinforces the government's authority over intra-state activities that might impact inter-state commerce.
Clinical Bulletin for Healthcare Professionals
Last updated September 18, 2006