Marijuana is a mixture of dried, shredded leaves, stems, seeds and flowers of the hemp plant (Cannabis sativa). The main active ingredient in marijuana is delta-9-tetrahydrocannabinol (THC). Marijuana and substances derived from it are also called cannabinoids.
Some cancer patients may ask about marijuana to control the symptoms of cancer or side effects of treatment, mainly nausea and vomiting or pain.
Use and claims
Although there is no scientific evidence to support these claims, people who support making marijuana available as a medical treatment say that the drug:
- helps relieve nausea and vomiting related to acquired immunodeficiency syndrome (AIDS) and cancer therapy
- Some chemotherapy drugs cause nausea and vomiting. People receiving chemotherapy are usually given anti-nausea (anti-emetic) drugs to prevent and control nausea and vomiting.
- Synthetic pill forms of marijuana are available for treating nausea and vomiting associated with cancer chemotherapy. Many doctors feel that they are not as effective as other anti-nausea drugs or combinations of these drugs; however, synthetic marijuana is sometimes used for people who do not respond to standard anti-nausea drugs.
- is effective in treating loss of appetite (anorexia), weight loss and cachexia
- Loss of appetite (anorexia) is a common problem in cancer patients. Anorexia and cachexia often occur together. To date there have been no studies that completed on marijuana's effects on appetite or weight, but a National Cancer Institute (NCI) study is evaluating whether or not marijuana used alone or in combination with another appetite-stimulating drug may be beneficial.
- There are a number of other ways to maintain and improve nutrition in people with cancer.
- is effective in treating chronic or severe pain
- Research studies done so far do not give a clear answer as to whether or not smoking marijuana helps relieve pain. However, the pill form is used by a number of pain clinics to manage chronic pain.
- is effective in treating a number of other conditions, such as epilepsy, multiple sclerosis, glaucoma and arthritis
None of these claims have been scientifically proven.
History and current status in Canada
A number of Canadians have requested that marijuana be legally available to people who could benefit from its use. In 1999 Health Canada released a research plan for the use of marijuana for medicinal purposes and two years later,federal regulations governing the "compassionate" use of medicinal marijuana came into effect.
Marijuana remains an illegal substance in Canada, but these temporary regulations provide eligible, seriously ill patients access to marijuana through Health Canada, while it is being researched as a possible medicine. The regulations define who is eligible to apply for, and may possess marijuana for medicinal reasons. For more information on eligibility for medical marijuana use, go to Health Canada's website.
Types
Two forms of marijuana are available:
- pill form
- Compounds that contain the active ingredient (THC) of marijuana, which can be taken by mouth.
- Dronabinol (Marinol) or nabilone (Cesamet) are considered controlled substances and are only available by prescription from a doctor.
- marijuana cigarettes
- The smoked form of marijuana.
A person must first talk to their doctor in order to get legal access to marijuana. They must apply for and receive special approval from Health Canada before they can legally use marijuana to treat their cancer pain or nausea.
Potential side effects and risks
Smoking marijuana and its pill forms may provide relaxation and a sense of well-being. However, there are some other side effects that may be unpleasant for some people:
- problems with memory and concentration
- sensory changes, including a lack of balance and slower reaction times
- physical changes
- dry mouth
- rapid heart beat
- a rise in blood pressure
The Canadian Cancer Society is concerned about the health risks associated with the long-term smoking of marijuana. The Society supports the clinical trials being conducted by Health Canada, which are looking at the medicinal benefits of marijuana use. Using marijuana to help relieve symptoms associated with cancer is an individual choice to be made after discussion with your doctor.
Research
Health Canada is conducting clinical trials that will provide evidence about the potential use and effectiveness of marijuana as a way of relieving symptoms of cancer and/or side effects of cancer treatment.
The trials will also provide information about the most effective way to give marijuana and its components to achieve the desired effects. The challenge is to come up with the appropriate dosage and way of giving marijuana that will produce the best effect, while minimizing side effects and longer-term harm and to identify any potential harmful interactions with other drugs.
For more information about research on the safety and effectiveness of smoked marijuana, go to the Canadian Institute of Health Research.