Review: Use of Medical Cannabis Products Not Associated with Increased Risk of “Serious Cardiovascular Events”

Salt Lake City, UT: Patients’ consumption of either purified or synthetic cannabinoids, including THC, is not associated with any increased risk of serious cardiovascular events, according to a review of clinical trial data published in the Journal of the American Pharmacists Association

An international team of investigators from the United States and Thailand reviewed data from 46 randomized clinical trials involving 2,800 patients. Subjects in the trials typically consumed oral doses of either synthetic forms of THC (e.g., nabilone or dronabinol) or purified cannabis extracts. 

The most common cardiovascular events reported by study subjects were non-serious in nature. These included increased risks of either hypotension (low blood pressure) or tachycardia (rapid heartbeat). By contrast, authors concluded, “None of the studies reported serious cardiovascular events.”

They cautioned, however, that few participants in the studies smoked cannabis flower – which may expose subjects to other ingredients or contaminants that could potentially trigger more serious adverse cardiovascular events. They further acknowledged that just under half of the trials reviewed excluded subjects from participation if they possessed underlying cardiovascular diseases, and that most of the studies were relatively short-term in duration. 

Investigators concluded: “Cannabis and cannabinoid use were associated with tachycardia, hypotension, and orthostatic hypotension. … In general, there is a paucity of data for other cardiovascular events among medical cannabis users, particularly serious cardiovascular events. … More trials with longer durations and in patients with existing cardio- vascular diseases or real-world evidence are needed to better determine the effects of cannabinoids on the cardio- vascular system.”

Israeli data published earlier this year reported that elderly patients with hypertension responded favorably to medical cannabis treatment and that it “was associated with a reduction in systolic and diastolic blood pressure, as well as heart rate.” 

Analyses of nationally representative samples of recreational marijuana consumers have reported mixed results regarding the relationship between cannabis and adverse cardiovascular events. A 2021 study of 57,000 US adults concluded, “After controlling for several confounding variables, we found that there was a decrease in the prevalence of cardiovascular events with marijuana use (Odds Ratio: 0.74).” By contrast, a 2020 review of nearly 134,000 US adults reported, “Frequent marijuana smoking is associated with significantly higher odds of stroke and myocardial infarction or coronary artery disease, with a possible role in premature cardiovascular disease.” Most recently, the results of a 2021 literature review of 67 studies published in The American Journal of Medicine concluded, “[M]arijuana itself does not appear to be independently associated with excessive cardiovascular risk factors.” Authors did caution, however, that “it can be associated with other unhealthy behaviors such as alcohol use and tobacco smoking that can be detrimental” to cardiovascular health.

NORML has previously cautioned that those persons either predisposed to or at high risk of cardiovascular issues, such as heart attack or stroke, may be at elevated risks from cannabis inhalation.

Full text of the study, “A systematic review and meta-analysis of randomized controlled trials of cardiovascular toxicity of medical cannabinoids,” appears in the Journal of the American Pharmacists Association.