Cardiac research through the side door.
Almost everybody who uses cannabis/marijuana (C/MJ) knows that it causes blood vessel dilation (for example: bloodshot eyes). The vasodilation is generalized and systemic; blood pressure goes down, followed by reflex tachycardia.
An Internet search of the subject Cannabis Hypertension Research provided a gold mine of articles dating back to Dr. Mechoulam's discovery of the structure of THC in 1970.
The earliest (that I could find) article on vasodilation was by Williams, et al in 1975. This was reported by Husain and Kahn in 1985. Their work is by far the best historic article on the subject. Few people seem to have found these older articles.
The physiological/pharmacological mechanisms seem to've been first published by Grotenhernmen in Russo's book, The Handbook of Cannabis Therapeutics in 2006. This was reported by Paul Armentano in NORML's Web page (NORML.org) entitled Hypertension, in 2010. The article was based upon reports by Batkal in 2004, Pacher in 2005 and Hilliard in 2000. (There are probably others; I will be reminded! -- but I couldn't find them.) There was a recent article by Gorelick in American Heart Journal in which Ramrimonabant, a CB-1 blocker was used, and it blocked the hypotensive (blood pressure lowering) effect of smoked C/MJ.
I read a recent clinical report about C/MJ for hypertension/high blood pressure but I have been unable to locate it again (Any help locating that is appreciated). When I returned to my computer to look up this subject, I was amazed to see what popped up and light bulbs went off over my head.
Dr. David Kendall at Queens' Medical Center in London first reported this vasodilating effect of Anandamide, the body's natural cannabinoid in 1998?!?
It seems that a young pharmacology PhD candidate, Yehoshua Moar, in Dr. Mechoulam's laboratory in Israel synthesized a C/MJ-like chemical which produces vasodilation and lowered blood pressure without the typical, sometimes unwanted euphoria.
This really caused several light bulbs to go off... I had assumed that the vasodilation and blood pressure drop was a short-term effect. My experience with about 5,000 medical marijuana patients was brought to the forefront. Neither I, myself nor my nurses and physician's assistants ever found a dangerously high blood pressure in any of the 5,000 patients. The pharmacological explanations seem clear to me. About 95% of my patients were long-time users and most smoked frequently. The average age was about 48 years, and the oldest was 90. This means that half of the patients were over 48 and certainly if they were NOT using C/MJ there would be many in the clinical hypertensive group.
The medical marijuana doctors group which I led now has more than 100,000 patients and none or few of them have reported dangerous clinical hypertension.
The California marijuana doctors have at least 300,000 total patients. I will be very interested to know if their experience with cannabis and hypertension is similar to my own.
Dr. Phil Leveque
March 14, 2010
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Cannabis / Marijuana for Hypertension