Cannabinoids and atherosclerotic coronary heart disease.

Marijuana is the most abused recreational drug in the United States. Cannabinoids, the active ingredients of marijuana, affect multiple organ systems in the human body. The pharmacologic effects of marijuana, based on stimulation of cannabinoid receptors CB1 and CB2, which are widely distributed in the cardiovascular system, have been well described. Activation of these receptors modulates the function of various cellular elements of the vessel wall, and may contribute to the pathogenesis of atherosclerosis. Clinically, there are reports linking marijuana smoking to the precipitation of angina and acute coronary syndromes. Recently, large published clinical trials with CB1 antagonist rimonabant did not show any significant benefit of this agent in preventing progression of atherosclerosis. In light of these findings and emerging data on multiple pathways linking cannabinoids to atherosclerosis, we discuss the literature on the role of cannabinoids in the pathophysiology of atherosclerosis. We also propose a marijuana paradox, which implies that inhalation of marijuana may be linked to precipitation of acute coronary syndromes, but modulation of the endocannabinoid system by a noninhalation route may have a salutary effect on the development of atherosclerosis.