Weeding out the truth: Cannabis-based medications for cancer patients

The Bottom Line

  • Nausea and vomiting are common and distressing side effects of chemotherapy.
  • Cannabinoids, active chemicals found in cannabis (marijuana), are used for medical purposes including treating nausea and vomiting.
  • Cannabinoids appear to work as well as conventional anti-sickness medications, but may cause side effects such as dizziness.

Cannabis – more commonly known as marijuana – continues to be a ‘smoking’ hot topic of discussion. The controversy over its legalization, production, use and distribution may be trending now but cannabis itself is far from being a new phenomenon. In the 1980s, cannabinoids – active chemicals found in cannabis – were approved for medical purposes such as treating the nausea and vomiting associated with chemotherapy (1). Up to 75% of cancer patients experience these symptoms (2) which are considered to be the most upsetting and stressful side effect of chemotherapy treatment (3).

But are cannabinoids any better than conventional anti-sickness medications? Or will they cause yet another set of worrisome side effects? To get clarity about the highs and lows of cannabis-based medication, a recent systematic review analyzed the results of 23 randomized controlled trials involving people with moderate to severe nausea and vomiting while undergoing chemotherapy cancer treatment (4).

The study participants were given one of two approved cannabinoids – nabilone and dronabinol – and monitored to see whether the medication effectively controlled nausea and/or vomiting in the short term (within 24 hours of chemotherapy) and in the longer term (more than 24 hours after treatment). The results were compared patients who received a placebo as well as with patients who received conventional anti-sickness medication.

What the research tells us

Cannabinoids did help control nausea and vomiting for people receiving chemotherapy and appeared to be just as effective as conventional anti-sickness medications, which means they may be a good alternative for people who don’t benefit from traditional drugs.

However there is a greater chance of side effects – some of the participants taking cannabinoids reported feeling “high”: dizzy, disoriented, sedated or uneasy. Despite that, in trials where participants were able to take and compare cannabinoids and conventional drugs, the majority preferred the cannabis-based medication. The review authors do note that the comparison to conventional drugs might not reflect current chemotherapy treatment options which have improved in the meantime.

The review hints at the potential benefits of cannabis-based drug therapies but more research is urgently needed, particularly in light of regulatory changes in Canada giving eligible patients access to “medical marijuana.”

Meanwhile, more high quality studies will help us know whether cannabis and cannabis-based medications truly are preferable to the drugs we have now, or whether it’s another instance of the grass being greener on the other side.

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Author Details


  1. Walsh D, Nelson KA, Mahmoud FA. Established and potential therapeutic applications of cannabinoids in oncology. Support Care Cancer. 2003; 11:137–43.
  2. Schwartzberg LS. Chemotherapy-induced nausea and vomiting: clinician and patient perspective. J Support Oncol. 2007; 5:5–12.
  3. Russo S, Cinausero M, Gerratana L et al. Factors affecting patient’s perception of anticancer treatments side-effects: an observational study. Expert Opin Drug Saf. 2014; 13(2):139–50.
  4. Smith LA, Azariah F, Lavender VT et al. Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy. Cochrane Database Syst Rev. 2015, Issue 11. Art. No.: CD009464. DOI: 10.1002/14651858.CD009464.pub2.

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