CA NORML Health Information
San Francisco, CA, April 2007: Vaporization is a "safe and effective" cannabinoid delivery mode for patients who desire the rapid onset of action associated with inhalation while avoiding the respiratory risks of smoking, according to clinical trial data to be published in the journal Clinical Pharmacology & Therapeutics.
Investigators at San Francisco General Hospital reported that use of the Volcano vaporizing device delivered "efficient" doses of THC to subjects in a "reproducible" manner while significantly reducing their intake of gaseous combustion toxins, including carbon monoxide. Eighteen subjects participated in the six-day study, which was sponsored by the California Center for Medicinal Cannabis Research.
"Vaporization of marijuana does not result in exposure to combustion gases, ... and [was] preferred by most subjects compared to marijuana cigarettes," authors concluded. "The Volcano [vaporizer] device is an effective and apparently safe vehicle for THC delivery, and warrants further investigation in clinical trials of cannabis for medical purposes."
Researchers reported that vaporization resulted in higher plasma concentrations of THC compared to smoked cannabis for up to 60 minutes following inhalation. Investigators also reported that subjects 'self-titrated' their intake of cannabis vapor, taking smaller and less frequent puffs when exposed to stronger marijuana. On average, the Volcano vaporizer exposed subjects to 54 percent of the applied dose of THC. Previous studies have shown that as much as 80 percent of the THC burned in cigarettes or water-pipes is lost in slipstream smoke.
A prior clinical trial assessing the safety and efficacy of the Volcano vaporizer published in 2006 in the Journal of Pharmaceutical Sciences also reported that the device delivers set doses of THC to subjects in a reproducible manner "while avoiding the respiratory disadvantages of smoking." The efficacy of the Volcano vaporizer was initially reported in a 2004 study co-sponsored by NORML and the Multidisciplinary Association for Psychedelic Studies (MAPS), which found that the device delivered vapor of high purity with practically no toxic tars or hydrocarbons.
Vaporization heats cannabis to a temperature where active cannabinoid vapors form (typically around 180-190 degrees Celsius), but below the point of combustion where noxious smoke and associated toxins (i.e., carcinogenic hydrocarbons) are produced (above 230 degrees Celsius).
Separate survey data published this week in the Harm Reduction Journal also reports that vaporization is subjectively associated with fewer respiratory symptoms than smoking cannabis.
Abstracts of the study, "Vaporization as a smokeless cannabis delivery system: a pilot study," are available online at: www.galenicom.com/medline/article/17429350/ca:66.
Abstracts of the study, "Decreased respiratory symptoms in cannabis users who vaporize," are available online at: www.harmreductionjournal.com/content/4/1/11/abstract.