SAN FRANCISCO, CALIFORNIA – Two new studies, one from the University of California, San Francisco, and the other from the University at Albany, State University of New York, provide strong evidence that technology now allows medical use of marijuana with the rapid action and easy dose adjustment of inhalation, but without the respiratory hazards associated with smoking. This is considered highly important, as the risks associated with smoke inhalation have been cited by both government officials and independent experts as a major argument against medical marijuana.
The San Francisco study, conducted by Dr. Donald Abrams and colleagues at UCSF and just published online by the journal Clinical Pharmacology and Therapeutics, compared a commercially available vaporizer called the Volcano to smoking in 18 volunteers.
The subjects inhaled three different strengths of marijuana either as smoked cigarettes or vaporized using the Volcano. Unlike smoking, a vaporizer does not burn the plant material, but heats it just to the point at which THC and the other active components, called cannabinoids, vaporize. The vapors are collected in a detachable plastic bag with a mouthpiece for inhalation.
The researchers then measured the volunteers’ plasma THC levels and the amount of expired carbon monoxide (CO), which is considered a reliable marker for the unwanted combustion products contained in smoke. The two methods produced similar THC levels, with vaporization producing somewhat higher levels, and were judged equally efficient for administration of cannabinoids.
The big difference was in expired CO. As expected, there was a sharp increase in CO levels after smoking, while “little if any” increase was detected after vaporization. “This indicates little or no exposure to gaseous combustion toxins,” the researchers wrote. “Vaporization of marijuana does not result in exposure to combustion gases, and therefore is expected to be much safer than smoking marijuana cigarettes.”
A second study, by Dr. Mitch Earleywine at the University at Albany, State University of New York and published in the Harm Reduction Journal, involved an Internet survey of nearly 7,000 marijuana users.
Participants were asked to identify their primary method of using marijuana (joints, pipe, vaporizer, edibles, etc.) and were asked six questions about respiratory symptoms. After adjusting for variables such as age and cigarette use, vaporizer users were 60 percent less likely than smokers to report respiratory symptoms such as cough, chest tightness or phlegm. The effect of vaporizer use was more pronounced the larger the amount of marijuana used.
“Our study clearly suggests that the respiratory effects of marijuana use can be decreased by use of a vaporizer,” Earleywine said. “In fact, because we only asked participants about their primary means of using marijuana, it’s likely that people who exclusively use vaporizers will get even more benefit than our results indicate, because no doubt some in our study used vaporizers most of the time but not all of the time.”
“Ten years ago, the Institute of Medicine’s landmark, White House-commissioned report found that marijuana has medical value,” said Rob Kampia, executive director of the Marijuana Policy Project in Washington, D.C. “In its report, the Institute of Medicine also called for the development of a non-smoked delivery system before making medical marijuana widely available. Now that we have such a delivery system, the prohibitionists’ final arguments against medical marijuana have been reduced to rubble.”
The Earleywine study is available online at www.harmreductionjournal.com/content/pdf/1477-7517-4-11.pdf.
– Abrams DI et al. Vaporization as a Smokeless Cannabis Delivery System: A Pilot Study. Clin Pharmacol Ther. 2007, Apr 11; [Epub ahead of print].
– Earleywine M and Barnwell SS. Decreased Respiratory Symptoms in Cannabis Users Who Vaporize. Harm Reduction Journal. 2007, 4:11.
Article from www.mpp.org
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