Top Things to Know: Medical Marijuana, Recreational Cannabis, and Cardiovascular Health
Published: August 05, 2020
- Attitudes towards recreational and medicinal use of cannabis have rapidly evolved. As of March 2020, 47 U.S. states, the District of Columbia, and 4 of 5 U.S. territories allow some form of cannabis use, while Canada and Uruguay now allow recreational use nationally.
- Cannabis use has risen considerably over the past decade, particularly among individuals 18-25 years of age.
- Cannabis formulations now include oral, sublingual, rectal, vaporized, or smoked; however, products for recreational use lack regulation, resulting in a lack of standard dosing, packaging, and labeling.
- Tetrahydrocannabinol (THC) and cannabidiol (CBD), 2 compounds derived from marijuana and hemp plants in the genus Cannabis, can have both direct and indirect effects on the cardiovascular (CV) system. THC may stimulate the sympathetic nervous system while inhibiting the parasympathetic nervous system, increase heart rate and supine blood pressure, cause platelet activation, and promote endothelial dysfunction and oxidative stress. CBD may reduce heart rate and blood pressure, improve vasodilation, and reduce inflammation, and lower vascular hyperpermeability.
- Safety signals have emerged regarding cannabis use and adverse CV outcomes, including myocardial infarction, heart failure, and atrial fibrillation; however, there is a paucity of rigorously performed studies. Carefully designed prospective short- and long-term studies regarding cannabis use and cardiovascular safety are needed.
- Cannabis smoke contains many of the same carcinogens and mutagens as tobacco smoke and is associated with health risks. Until the pathophysiology of e-cigarette or vaping product use-associated lung injury (EVALI) is better understood, vaping cannabis, especially when it is mixed with vitamin E acetate oils, should be avoided. Given the increased incidence of severe COVID-19 lung injury among tobacco smokers and e-cigarette users, the same association may exist for smoking or vaping cannabis, particularly among those with underlying CV conditions. If people choose to use cannabis for its medicinal or recreational effects, oral and topical forms may reduce some of these potential harms.
- Cannabis use disorder, withdrawal, and hyperemesis syndrome are serious adverse events that should be particularly discussed with chronic heavy users and recognized by clinicians.
- Drug-drug interactions can exist and should be anticipated as THC has the potential to inhibit CYP 3A4/4, 2C9, 2C19, and 2D6 while CBD can inhibit CYP 3A4/5, 2C19, 2D6, and 1A2, which could lead to therapeutic failure or toxicity of a wide range of drugs, including antidepressants, cholesterol lowering, antiarrhythmics, antivirals and antimicrobials.
- A lack of definitive evidence exists regarding the CV effects of cannabis in several vulnerable populations such as adolescents, older adults, pregnant women, transplant recipients, and those with underlying CV disease.
- Clinicians need greater knowledge of the various cannabis products and health implications during their initial training and continuing education, and must be alert to the possibility that the use of cannabis or its potent synthetic analogues might be the underlying cause of CV events and other health problems.
Citation
Page RL 2nd, Allen LA, Kloner RA, Carriker CR, Martel C, Morris AA, Piano MR, Rana JS, Saucedo JF; on behalf of the American Heart Association Clinical Pharmacology Committee and Heart Failure and Transplantation Committee of the Council on Clinical Cardiology; Council on Basic Cardiovascular Sciences; Council on Cardiovascular and Stroke Nursing; Council on Epidemiology and Prevention; Council on Lifestyle and Cardiometabolic Health; and Council on Quality of Care and Outcomes Research. Medical marijuana, recreational cannabis, and cardiovascular health: a scientific statement from the American Heart Association [published online ahead of print August 5, 2020]. Circulation. doi: 10.1161/CIR.0000000000000883.