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Medical marijuana (or medical cannabis) refers to the way people use part of the marijuana plant to help deal with a medical condition. The U.S. Food and Drug Administration does not recognize or approve marijuana as a medicine.
But, scientific study of the active chemicals in marijuana, called cannabinoids, has led to the development of two FDA-approved medications. These studies are leading to the development of new pharmaceuticals that may harness therapeutic benefits of cannabinoids while minimizing or eliminating the harmful side effects, such as the high produced by eating or smoking marijuana leaves.
Cannabinoids are a large family of chemicals related to delta-9-tetrahydrocannabinol (THC), marijuana’s main psychoactive (mind-altering) ingredient. Besides THC, the marijuana plant contains more than 100 other cannabinoids. Scientists and manufacturers of “designer” drugs have also synthesized numerous cannabinoids in the laboratory like “spice,” “K2” and “synthetic K2” (which are extremely potent and, when abused, have led to serious health consequences). The body also produces its own cannabinoid chemicals (called endocannabinoids), which play a role in regulating pleasure, the immune system, memory, thinking, concentration, movement, coordination, sensory and time perception, appetite, and pain.
Currently the two main cannabinoids of interest therapeutically are THC and cannabidiol (CBD), found in varying ratios in the marijuana plant. THC stimulates appetite and reduces nausea (and there are already approved THC-based medications for these purposes), but it may also decrease pain, inflammation, and spasticity. CBD is a non-psychoactive cannabinoid that may also be useful in reducing pain and inflammation, controlling epileptic seizures, and possibly even treating psychosis and addictions.
An FDA-approved drug called Dronabinol (Marinol®) contains THC and is used to treat nausea caused by chemotherapy and wasting disease (extreme weight loss) caused by AIDS. Another FDA-approved drug called Nabilone (Cesamet®) contains a synthetic cannabinoid similar to THC and is used for the same purposes.
Why isn’t the marijuana plant an FDA-approved medicine?
The FDA requires carefully conducted studies in large numbers of patients (hundreds to thousands) to accurately assess the benefits and risks of a potential medication. Thus far, there have not been enough large-scale clinical trials showing that benefits of the marijuana plant (as opposed to specific cannabinoid constituents) outweigh its risks in patients with the symptoms it is meant to treat.
The known safety concerns of marijuana include impairment of short-term memory; altered judgment and decision making; and mood effects, including severe anxiety (paranoia) or even psychosis (loss of touch with reality), especially following high-dose exposures. Marijuana also significantly reduces motor coordination and slows reaction time, which makes it very dangerous to use before driving a car. Additionally, although we do not yet know whether smoking marijuana contributes to lung cancer risk, it can cause or worsen other respiratory problems such as bronchitis or chronic cough.