Agriculture Reference
In-Depth Information
Other synthetic cannabinoids are currently
the subject of experimental studies. These
include menabitan, pirnabine and naboctate.
Rimonabant, a cannabinoid receptor antago-
nist, was commercialized as an appetite sup-
pressant and for the treatment of obesity, but
was withdrawn from the market in 2008 after
it was found to have provoked serious psycho-
logical side effects, including depression and
attempted suicide.
A review of 31 studies on cannabinoids
published between 1966 and 2007 shows that
their use in the short term has not resulted in
any loss of life, serious problems, hospitaliza-
tion or serious disability. In 96.6% of published
cases, the iatrogenic effects were described as
central or peripheral nervous system distur-
bances (loss of balance, dizziness and paraes-
thesia) (Wang
et al
., 2008). The studies
conducted do not, however, allow us to con-
firm the long-term innocuity of such treatments
(Wang
et al
., 2008). For further information,
see Degenhardt and Hall (2008).
to be any more effective than standard
treatments (antipsychotic drugs used as
anti-emetics, the sulpiride for example)
and have a poor therapeutic index accord-
ing to a review of the literature up to 2000
(Tramer
et al
., 2001).
A recent literature review, however, sug-
•
gests that the therapeutic index is, in fact,
superior to that of antipsychotic drugs
used for this indication (Machado Rocha
et al
., 2008).
It is important that we put into context the
potential value of cannabinoids in the treat-
ment of chemotherapy-induced and radiother-
apy-induced nausea and vomiting following the
commercialization in the early 1990s of a
group of highly effective anti-emetics (5HT3
serotonin antagonists called setrons) (Michalon,
2005). Cannabinoids can potentiate the effect
of these anti-emetics and therefore increase
their effectiveness (Michalon, 2005).
The use of cannabis can limit the nausea
induced by certain antiretroviral treatments
and can therefore improve treatment compli-
ance (De Jong
et al
., 2005).
15.7 Various Controversial
Medical Indications
15.7.2 Treatment of pain
The range of recommended indications for can-
nabinoids is very broad. There have, however,
been very few rigorous scientific trials to evalu-
ate these uses. Many publications deal only with
a small cohort of patients or report on individ-
ual cases. The status and reputation of cannabis
does not lend itself well to further studies, even
if public opinion appears to the use of this plant
and its derivatives in medicine.
Cannabinoids possess a well-recognized cen-
tral analgesic effect (Manzanares
et al
., 2006).
This is probably linked to the inhibition of
GABAergic conduction associated with their
interaction with CB1 receptors (Hosking and
Zajicek, 2008). This action is similar to that of
codeine and therefore inferior to that of mor-
phine (Campbell
et al
., 2001). Cannabinoids
can act to depress the central nervous system
and this effect can limit their worth (Campbell
et al
., 2001; Michalon, 2005).
It may, however, be worth investigating
further the value of cannabinoids and cannabis
in the treatment of certain pain and, in particu-
lar, pain associated with deafferentation
(Manzanares
et al
., 2006; Hosking and Zajicek,
2008; Martin Fontelles and Goicoechea Garcia,
2008). If trials on patients suffering from
cancers or multiple sclerosis have demonstrated
a reduction in pain associated with the disease
following the administration of cannabis
extracts (Sativex©), it is possible that synthetic
15.7.1
Prevention and treatment of
nausea and vomiting
Various cannabinoids exert a significant anti-
emetic effect and anti-nausea effect in patients
receiving chemotherapy or radiotherapy. As is
often the case, the opinion of various authors
on this subject varies:
•
The synthetic cannabinoids that have been
trialled clinically (nabilone, dronabinol and
levonantradol) have not shown themselves
