High blood pressure, or hypertension, afflicts an estimated one in four American adults. This condition puts a strain on the heart and blood vessels and greatly increases the risk of stroke and heart disease.
Emerging research indicates that the endogenous cannabinoid system plays a role in regulating blood pressure, though its mechanism of action is not well understood. Animal studies demonstrate that anandamide and other endocannabinoids profoundly suppress cardiac contractility in hypertension and can normalize blood pressure,[2-3] leading some experts to speculate that the manipulation of the endocannabinoid system "may offer novel therapeutic approaches in a variety of cardiovascular disorders."
The administration of natural cannabinoids has yielded conflicting cardiovascular effects on humans and laboratory animals.[5-9] The vascular response in humans administered cannabis in experimental conditions is typically characterized by a mild increase in heart rate and blood pressure. However, complete tolerance to these effects develops quickly and potential health risks appear minimal.[10-11]
Cannabinoid administration in animals is typically associated with vasodilation, transient bradycardia and hypotension, as well as an inhibition of atherosclerosis (hardening of the arteries) progression.[13-15] The administration of synthetic cannabinoids have also been shown to lower blood pressure in animals and have not been associated with cardiotoxicity in humans.
At this time, research assessing the clinical use of cannabinoids for hypertension is in its infancy and potentially higher-risk populations are largely cautioned by experts to refrain from cannabis smoking.
 Franjo Grotenhermen. 2006. Clinical pharmacodynamics of cannabinoids. In Russo et al (Eds) Handbook of Cannabis Therapeutics. Binghampton, New York: Haworth Press.
 Batkai et al. 2004. Endocannabinoids acting at cannabinoid-1 receptors regulate cardiovascular function in hypertension. Circulation 110: 1996-220.
 Pacher et al. 2005. Blood pressure regulation by endocannabinoids and their receptors (PDF). Neuropharmacology 48: 1130-1138.
 Ribuot et al. 2005. Cardiac and vascular effects of cannabinoids: toward a therapeutic use? Annales de Cardiologie et d’Angeiologie (France) 54: 89-96.
 Steven Karch. 2006. Cannabis and cardiotoxicity. Forensic Science, Medicine, and Pathology. 2: 13-18.
 Rodondi et al. 2006. Marijuana use, diet, body mass index and cardiovascular risk factors. American Journal of Cardiology 98: 478-484.
 Reese Jones. 2002. op. cit.
 Steffens and Mach. 2006. Towards a therapeutic use of selective CB2 cannabinoid receptor ligands for atherosclerosis. Future Cardiology 2: 49-53.
 Steffens et al. 2005. Low dose oral cannabinoid therapy reduces progression of atherosclerosis in mice. Nature 434: 782-786.
 Steffens and Mach. 2006. Cannabinoid receptors in atherosclerosis. Current Opinion in Lipidology 17: 519-526.
 Steven Karch. 2006. op. cit.
Francois Mach. 2006. New anti-inflammatory agents to reduce atherosclerosis. Archives of Physiology and Biochemistry 112: 130-137.
 Thomas et al. 2014. Adverse cardiovascular, cerebrovascular, and peripheral vascular effects of marijuana inhalation: what cardiologists need to know. American Journal of Cardiology 113: 187-190.