Nausea is a common side effect of cancer and its treatments, affecting up to 70 percent of patients getting treated for the disease. Many different types of medications can help to prevent or control nausea in these patients. However, two undesirable effects often occur when they're used: side effects -- such as headaches, tiredness and constipation -- and resistance to treatment, where efforts to control nausea fail. Thus, there's a need for new treatments that relieve nausea with as few side effects as possible.
Marijuana, also known as cannabis, may bring hope to patients who suffer nausea during chemotherapy. A native of Central Asia, this plant has a long history of use as a nausea treatment. However, the mechanism by which it exerts its effects had, until recently, remained a mystery. Research carried out in the 1960s revealed that marijuana contains chemical compounds called cannabinoids, which are responsible for its physical and psychological effects. Of these cannabinoids, the most important are delta-9-tetrahydrocannabinol (delta-9-THC) and cannabidiol (CBD).
With the discovery of cannabinoids, scientists were able to create synthetic cannabinoids -- chemicals made to mimic the effects of the natural cannabinoids found in the marijuana plant. Two synthetic cannabinoids, dronabinol and nabilone, were later approved by the U.S. Food and Drug Administration (FDA) for chemotherapy-induced nausea and vomiting. These drugs are usually prescribed to patients who have tried other anti-nausea medications without success, and are taken by via oral capsule several times a day during a chemotherapy cycle.
Despite the FDA's approval of dronabinol and nabilone as treatment for chemotherapy-induced nausea and vomiting, research into the benefits that the actual marijuana plant can confer is progressing. Research commissioned by the Swiss Federal Office of Public Health, and published in the Journal of the American Medical Association in June 2015, supports using cannabinoids as a treatment for nausea from chemotherapy. Researchers analyzed data from 28 studies, and found that patients using cannabinoids were more likely to report reductions in nausea and vomiting than those given a placebo. Science is yet to show the exact mechanism for all the cannabinoids found in the marijuana plant, but evidence suggests that cannabinoids work better together than in isolation: a discovery that has been termed the entourage effect.
There's a growing interest among researchers in treating children with nausea and other cancer symptoms with medical marijuana, although the studies are limited. In a paper titled, "An Efficient New Cannabinoid Antiemetic in Pediatric Oncology," and published in the journal Life Sciences in 1995, researchers in Jerusalem, Israel, revealed that delta-8-tetrahydrocannabinol (delta-8-THC), a cannabinoid with fewer mood-altering effects than the main marijuana cannabinoid, delta-9-THC, successfully treated chemotherapy-induced nausea and vomiting in children with negligible side effects. The study involved eight children aged 3 to 13 who had various blood cancers and had been treated with different anticancer drugs for up to eight months. Each of the children were given delta-8-THC two hours before chemotherapy and every six hours afterward for 24 hours.
Nausea affects a significant number of cancer patients, and standard treatments often fall short of patients' needs. Medical marijuana is potentially more effective than existing treatments and may have fewer side effects.