Cannabis Use Is Associated With a Small Increase in the Risk of Postoperative Nausea and Vomiting

A Retrospective Machine-learning Causal Analysis

Wendy Suhre; Vikas O'Reilly-Shah; Wil Van Cleve


BMC Anesthesiol. 2020;20(115) 

In This Article


Medicinal use of cannabis was first described in 1840 by W.B. O'Shaughnessy, a medical doctor and chemist in Calcutta, who described its use for the treatment of acute and chronic rheumatism, rabies, tetanus, cholera, and infantile convulsions.[1] Cannabis is currently classified as a Schedule 1 drug in the United States, a classification for drugs considered by the Drug Enforcement Agency to have no accepted medical use and an unacceptable risk of abuse.[2] Beginning in 1996, a gradual process of cannabis legalization has taken place in the US, with 33 states as well as the District of Columbia permitting medical use and 14 US states and territories presently allowing recreational use of cannabis.[3] In Washington State, where this research was conducted, recreational use of cannabis by adults 21 years of age and older was legalized in 2012.

In the nineteenth century, Dr. O'Shaughnessy described the use of hemp seeds to treat many diseases, and specifically noted that they "allayed vomiting" in cholera patients. Today, the cannabinoids present in cannabis are used in a medical context to treat various medical conditions, among them chemotherapy induced nausea and vomiting (CINV). Multiple studies using synthetic cannabinoids have shown cannabis to be as effective as other antiemetics for this purpose.[4–6]

As cannabinoid compounds have been shown to be effective treatments for CINV, it seems reasonable to conjecture that cannabis use could exert a prophylactic or therapeutic effect for patients at risk for or suffering from postoperative nausea and vomiting (PONV). While several studies have examined the role of therapeutically administered cannabinoids in the prevention and treatment of PONV, almost nothing is known about the impact of chronic use of cannabis on the risk for developing PONV.[7–10] The present investigation examines whether an association exists between patient-described use and/or frequency of cannabis and the occurrence of PONV following general anesthesia.