Journal of the California Cannabis Research Medical
Recommendation to Patients: "Don’t
By Dale Gieringer
Patients receiving physician approval to use cannabis should be warned that
chemicals released when the dried leaves and/or flowers are burned put heavy
smokers at increased risk for bronchitis and respiratory infections.1
The risk can be avoided, however, by an alternative delivery system: a device
called a vaporizer that heats dried cannabis to a temperature where cannabinoid
vapors are released, but below the point of combustion, where noxious and carcinogenic
smoke toxins are formed. Patients can thus inhale the pharmaceutically active
cannabinoids without exposing themselves to harmful respiratory toxins.
Although the principle of vaporization has been known for a long time, until
recently there were no scientific studies demonstrating its feasibility. The
situation has changed thanks to a pair of studies sponsored by California NORML
and MAPS at Chemic Laboratories in Canton, Mass.
The first, completed in 2001, tested a vaporizer known as the M-1 Volatizer,
(www.volatizer.com). The M-1 resembles an auto cigarette lighter that is designed
to fit over a pipe or bong bowl and heat the sample to the point of vaporization.
Efficient vaporization occurs around 180° - 190° C (356° - 374° F)
while combustion occurs around 230° C (446° F).
The study found that the M-1 delivered effective levels of THC, CBD and CBN,
while completely eliminating three specific toxins —naphthalene, benzene, and
toluene— in the solid phase of the vapor. A qualitative reduction in carbon
monoxide was also detected.2
The second vaporizer study, released in April of this year, looked at a much
wider range of toxins, focusing particularly on the highly carcinogenic polynuclear
aromatic hydrocarbons (PAHs), a prime suspect in smoking-related cancers. The
device tested was the “Volcano” (www.storz-bickel.com), a vaporizer that has
become extremely popular with medicinal cannabis users who can afford it —the
retail price is around $600 due to its high-tech innovative design.
The Volcano consists of a heater with a sample chamber on top. An air pump
blows hot air through the sample into a balloon, where the vapors are collected.
After being filled. the balloon is detached and fitted with a valved mouthpiece,
through which the vapors are inhaled. The novel design has been patented in
the U.S. and internationally by Storz & Bickel GmbH&Co. KG, Tuttlingen,
The study compared Volcano vapors to smoke produced by combusted marijuana.
The cannabis was the standard product provided to researchers by the National
Institute on Drug Abuse, containing 4% THC. Analysis by gas chromatograph mass
spectrometer (GCMS) showed that the Volcano vapor consisted almost entirely
of THC (95%), with traces of cannabinol (CBN), another cannabinoid. The remaining
5% consisted of small amounts of caryophyllene, a fragrant oil in cannabis
and other plants, and two other components of uncertain origin.
In contrast, analysis of the combusted smoke showed a potpourri of at least
111 different gas phase components, including six known PAHs. Non-cannabinoids
accounted for as much as 88% of the total gas content of the smoke. 3
A separate study was undertaken to determine the efficiency of the Volcano
in delivering THC. Three balloonfuls of vapor were drawn from the sample and
analyzed quantitatively via high-pressure liquid chromatography. On average,
46% of the THC from the sample appeared in the vapor. This compares favorably
with the efficiency of marijuana cigarettes as observed in other studies, which
can fall below 25% due to loss of THC in sidestream smoke.
The efficiency of the Volcano appears to be due to the innovative
balloon containment system, which prevents loss of vapor as well as
providing a fixed dosage quantity useful for controlled studies. It
is possible that higher efficiencies could have been realized by stirring
the sample around and drawing another balloonful, as recommended by
The Volcano study provides the most compelling evidence to date that vaporizers
offer an effective means of eliminating the respiratory hazards of marijuana
smoking. In its 1999 report on medical marijuana, the Institute of Medicine
recommended against long-term use of smoked marijuana because of the health
risks of smoking. However, the IOM report was silent on the subject of vaporizers.
Foes of medical marijuana such as the California Narcotics Officers Association
have continued to harp on the health hazards of smoking as an objection to
legalization. However, advocates can now reply that the vaporizer studies put
these objections to rest.
At present, the only FDA-approved method for administering marijuana to human
research subjects is via smoking NIDA-supplied cigarettes. NORML and MAPS are
supporting efforts to have vaporizers approved by the FDA. Donald Abrams, MD,
of the University of California, San Francisco, has submitted a grant proposal
to the California Center for Medical Cannabis Research in San Diego to test
the Volcano in human subjects. If the protocol is funded and the Volcano approved
by the FDA for human research, it will be the first human study using a vaporizer.
In the meantime, vaporizers are enjoying growing popularity in the medical
marijuana community. Dozens of models are currently on the market, ranging
from homemade glass vaporization pipes to sophisticated electronic devices.
To avoid the paraphernalia laws, most are discreetly sold as “herbal vaporizers.” .