3. Umbruch 4.4..2005 - Online Pot

186 L.A. Parker et al.
ing nausea, as well as delayed nausea and vomiting and ANV when they do
occur. There is some evidence that cannabis-based medicines may be effective
in treating these intractable symptoms. Abrahamov et al. [59] evaluated the
anti-emetic effectiveness of ∆ 8 -THC, a close but less psychoactive relative of
∆ 9 -THC, in children receiving chemotherapy treatment. Two hours before the
start of each cancer treatment and every 6 h thereafter for 24 h, the children
were given ∆ 8 -THC as oil drops on the tongue or in a bite of food. After a total
of 480 treatments, the only side effects reported were slight irritability in two
of the youngest children (3.5 and 4 years old); both acute and delayed nausea
and vomiting were controlled.
Furthermore, Tramer et al. [56] conclude that many patients have a strong
preference for smoked marijuana over the synthetic cannabinoids delivered
orally. This could be for various reasons: (1) possible advantages of self-titration
with the smoked marijuana, (2) the difficulty of swallowing the pills while
experiencing emesis, (3) faster speed of onset for the inhaled or injected
∆ 9 -THC than oral delivery, or (4) a combination of the action of other cannabinoids
with ∆ 9 -THC that are found in marijuana. Although many marijuana
users have claimed that smoked marijuana is a more effective anti-emetic than
oral ∆ 9 -THC, no controlled studies have yet been published that evaluate this
possibility. Most of the evidence is based upon anecdotal testimonials, such as
that of the late Stephen Jay Gould [60]: “I was miserable and came to dread
the frequent treatments with an almost perverse intensity. …Absolutely nothing
in the available arsenal of medications worked at all. Marijuana, on the
other hand, worked like a charm.”
Smoking marijuana may represent a more efficient and rapid route of
administration. However, it is also possible that as marijuana contains over 60
other compounds, some of these additional consitutents may contribute to the
anti-emetic/anti-nausea effect. Another major cannabinoid found in marijuana
is cannabidiol (CBD); however, unlike ∆ 9 -THC, CBD does not produce psychomimetic
effects [61]. CBD, unlike ∆ 9 -THC, does not bind to the known
cannabinoid receptors. It may act by blocking the reuptake of anandamide (an
endogenous cannabinoid), or by inhibiting enzymatic hydrolysis of anandamide,
or bind with some as-yet-unknown cannabinoid receptor [61–63]. In
mice, CBD is a highly effective anti-inflammatory agent [63], as well as a neuroprotective
antioxidant [64]. In shrews, CBD inhibits cisplatin-induced [32]
and lithium-induced [31] emesis and in rats CBD inhibits nausea [38]. These
effects are described more fully below.
Effects of cannabinoids on emesis in animals
In order to understand the pathways involved in the response to anti-cancer
therapies to develop appropriate drug therapies, animal models have been
developed. Since rats and mice do not vomit in response to a toxin challenge,
it was necessary to develop other animal models of emesis. As indicated in