CLINICAL RESEARCH POSTER PRESENTATION ABSTRACTS
Please note: All posters will be displayed in
Salons 10-12.
FRIDAY, 10:15-11:00 AM
Abrams DI, Vizoso HP, Shade SB, Jay C, Kelly ME, Benowitz
N.
Vaporization as a smokeless cannabis delivery system:
a pilot study.
San Francisco General Hospital dabrams@php.ucsf.edu
PURPOSE: The Institute of Medicine report published
in 1999 suggested that although marijuana may have potential therapeutic
value, smoking was not a desirable delivery system for cannabis. A 6-day
"proof of concept" pilot study was proposed to investigate vaporization
using the VolcanoĻ device as an alternative means of delivery of inhaled
Cannabis sativa, to characterize preliminary pharmacokinetic and
pharmacodynamic effects and to determine whether it may be an appropriate
system for use in clinical effectiveness studies.
METHODS: Eighteen healthy subjects were recruited
and admitted to the inpatient ward of the General Clinical Research
Center (GCRC) at San Francisco General Hospital to investigate the delivery
of cannabinoids by vaporization of marijuana compared to marijuana smoked
in a standard cigarette. One dose ( 1.7, 3.4 or 6.8% tetrahydrocannabinol)
and delivery system (smoked marijuana cigarette or vaporization system)
was randomly assigned for each of the six study days. The primary endpoint
was the comparison of plasma concentrations of delta-9-tetrahydrocannabinol
(THC), cannabidiol, cannabinol, and metabolites, including 11-OH-THC
resulting from inhalation of cannabis after vaporization vs smoking.
Expired carbon monoxide was measured to evaluate whether the vaporizer
reduces exposure to gaseous toxins as a secondary endpoint. We also
evaluated physiologic and neuropsychologic effects and queried patients
for their preference of blinded dose day and delivery method. Adverse
events were collected.
RESULTS: 21 participants were enrolled to obtain
the 18 who completed the 6-day inpatient study. 15 men and 3 women,
mean age 30 years, were included in the final analysis. The analysis
suggests that the peak plasma concentration levels of vaporized cannabis
are similar to those of smoked cannabis. Plasma concentrations at 30
minutes after drug administration and beyond were significantly higher
in vaporized cannabis as compared to smoked cannabis. Carbon monoxide
levels were significantly reduced with vaporization compared with smoked
cannabis. 14 participants preferred vaporization, 2 smoking and 2 reported
no preference. No adverse events were observed.
CONCLUSION: Vaporization of cannabis is a safe
mode of delivery. Participants had a clear preference for vaporization
over smoking as a delivery system for the cannabis used in this trial.
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