Marijuana and chemotherapy

Hey Alice,

How does marijuana help a cancer patient undergoing chemotherapy?

Dear Reader,

Marijuana has been documented for its medicinal uses for thousands of years. Although it’s still being officially determined whether or not smoking marijuana is an effective way to manage the side effects of chemotherapy, the chemical compounds in marijuana, cannabinoids, are known to generate positive effects in some people experiencing conditions such as anorexia, nausea and vomiting, pain, insomnia, and depression.

These positive effects may seem favorable for some patients undergoing chemotherapy. Many patients lose their desire to eat and experience nausea and vomiting. Others develop a condition called cachexia, in which they lose a significant portion of their body weight, both fat and muscle. This condition, especially when combined with the loss of appetite and nausea, may cause those being treated for cancer to feel physically weak and emotionally drained. The National Cancer Institute (NCI) explains that maintaining an adequate weight and absorbing sufficient nutrients can help patients feel, look, and function better and may even help their bodies tolerate cancer therapy.

In order to combat the harsh side effects of chemotherapy, patients are given drugs called antiemetics in order to reduce nausea and increase appetite. While the United States Food and Drug Administration (FDA) hasn’t approved the use of marijuana to treat any medical condition, it has approved the use of prescription cannabinoids, dronabinol and nabilone, for the management of nausea and vomiting caused by chemotherapy. These drugs either contain or resemble THC (delta-9-tetrahydrocannabinol), one of the main cannabinoids in marijuana. THC aids in pain relief and reducing nausea, but it’s also psychoactive, meaning it causes a “high.” This potential to cause a “high” may seem uncomfortable for some patients and is of more concern for patients dealing with mania, depression, or other mental illnesses. Other adverse effects such as increased heart rate and decreased blood pressure have been reported, indicating a need to have meaningful conversations with a health care provider before taking these prescription drugs.

While these prescription cannabinoids are now available for chemotherapy patients, some people may still feel that this form of THC isn’t as effective as smoking marijuana in its natural, plant form. This might be because one of the other main cannabinoids of marijuana, cannabidiol, isn’t contained in the prescription cannabinoids. Cannabidiol has anti-anxiety effects that some patients find helpful, but smoking marijuana contains its own set of possible risks. Studies have provided evidence that smoking marijuana may cause cancer, but this still needs to be further validated. Additionally, research is still inconclusive if smoking marijuana is viable for treating the side effects caused by chemotherapy. This effort is further exacerbated by the fact that marijuana is still classified as a Schedule I drug by the Drug Enforcement Administration (DEA) and is federally still considered illegal, making any clinical studies involving its use an arduous task. To further complicate matters, laws on using marijuana either medically or recreationally vary state-by-state, limiting its accessibility based upon location. Still, preclinical evidence and anecdotes from patients show promise for marijuana in managing chemotherapy.

While smoking marijuana still needs more evidence as an effective treatment for managing chemotherapy side effects, THC-derived drugs such as dronabinol and nabilone are approved.

Last updated Nov 20, 2020
Originally published Jun 18, 1999

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