Is Medical Marijuana Safe?

By Jane Farrell

Editor’s note: As of earlier this year, 20 states have legalized the use of marijuana for some serious medical conditions, including cancer, glaucoma and HIV/AIDS. But using medical marijuana isn’t a casual decision. Here, the National Institute on Drug Abuse offers (NIDA) offers a briefing on the most controversial medicine of our time:

According to NIDA, the term “medical marijuana” refers to the whole unprocessed marijuana plant or its crude extracts. The federal Food and Drug Administration (FDA) doesn’t recognize or approve those substances as medicine.

But scientists have developed two FDA-approved medications that contained cannabinoids, the active chemicals in marijuana. There’s also ongoing research into new drugs that provide the benefits of marijuana without any of the harmful effects produced by eating or smoking marijuana leaves.

Cannabinoids are a large family of chemicals related to delta-9-tetrahydrocannabinol (THC), marijuana’s main mind-altering ingredient. NIDA says that the body also produces its own cannabinoid chemicals (called endocannabinoids), which play a role in regulating pleasure, memory, thinking, concentration, movement, coordination, sensory and time perception, appetite, and pain.

The two main cannabinoids of interest in research are THC and cannabidiol (CBD). THC stimulates appetite and reduces nausea, but it may also decrease pain, inflammation, and spasticity (extreme muscle rigidity). CBD is a cannabinoid without mind-altering properties and could help in reducing pain and inflammation, controlling epileptic seizures, and possibly even treating psychosis and addictions.

Some THC-based medications are already approved by the FDA: 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®) has a synthetic substance similar to THC and is used for the same purposes.

Additionally, a drug called Sativex®, which contains equal parts THC and CBD, is approved in the UK and several European countries to treat spasticity caused by multiple sclerosis (MS). In the U.S., it is in a Phase III clinical trial to evaluate its safety and effectiveness in treating cancer pain.

But the FDA hasn’t approved use of the whole marijuana plant (as opposed to components) because there aren’t any large clinical trials to show whether it would be effective and what kind of side effects or risks it would have.

NIDA lists these safety concerns for marijuana: impairment of short-term memory; altered judgment; mood effects, including paranoia and psychosis, especially following high-dose exposures. Marijuana also reduces motor coordination and slows reaction time, and that is dangerous when driving. Smoking marijuana can cause or aggravate other respiratory problems like chronic cough or bronchitis. NIDA says it’s not known yet whether marijuana can cause lung cancer.

(Marijuana also has negative effects on adolescents and mothers-to-be. It can cause permanent cognitive impairment if used habitually during adolescence, when the brain is developing. And it’s been linked to neurological problems in babies and trouble in school in later childhood.)

Experts are still analyzing the effects of regular medical use of marijuana, since that is a fairly new phenomenon. Because of that, NIDA says, its long-term effects on people who are ill aren’t known. It is possible, NIDA says, that people suffering from ailments like cancer and AIDS may be more vulnerable to the drug’s side effects. Scientists need to do more research to see if that’s the case.

Finally, NIDA says, one of the biggest safety concerns is that though many people believe otherwise, marijuana can be addictive. About 9 percent of people who try it will become addicted, and the number jumps to 25 to 50 percent among daily users.

For more information, visit National Institute on Drug Abuse.