Although marijuana is often not considered to have serious cardiovascular effects, in animal studies THC, the active ingredient in cannabis, has been found to affect cardiovascular activity through a number of mechanisms, including inhibition of adrenal catecholamine secretion and modulation of cardiac vagal tone through inhibition of norepinephrine release from sympathetic neurons (1).

There have also been reports of temporal association between marijuana use and acute coronary syndrome, cardiac arrhythmias, cerebrovascular events, including TIA’s, strokes, and cerebral vasospasm, as well as peripheral vascular events, including arteritis, Raynaud’s phenomenon, and digital necrosis (2).

In a recent comprehensive case series, about 2.0 % of all cannabis-associated adverse events were reported cardiovascular in nature, with 25% resulting in death (2). However, it is often difficult to determine the relative contribution of marijuana and other concurrent conditions or substances (e.g. alcohol and tobacco) when cardiovascular complications occur. More research in this area is needed.

References

1. Szabo B, Nordheim U, Niederhoffer N. Effects of cannabinoids on sympathetic and parasympathetic neuroeffector transmission in the rabbit heart. J Pharmacol ExpTher 2001; 297:819-826. http://jpet.aspetjournals.org/content/297/2/819

2. Jouanjus E, Lapeyre-Mestre M, Micallef J, et al. Cannabis use: signal of increasing risk of serious cardiovascular disorders. J Am Heart Assoc 2014; 3:e000638.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187498/

Contributed by Pierre Ankomah, MD, Boston, MA

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