Biomedical Engineering Reference
In-Depth Information
disease, gastrointestinal, tremors, and convulsions may occur [
11
] . The effects of
MDMA and related compounds are similar to those of amphetamine stimulants;
they can also cause acute side effects and somatic neurotoxicity [
17
] .
4.2.4
Pharmacokinetics
The main metabolic reaction is the deamination of amphetamine with the formation
of phenylacetone, which is subsequently oxidized to benzoic acid, then conjugated
with glycine to form hippuric acid. Side reactions include aromatic hydroxylation to
form 4-hydroxyamphetamine (an active metabolite), the stereoselective b -hydroxy-
lation for the isomer (+) of amphetamine leading to the formation of norephedrine
(phenylpropanolamine) and finally the N-oxidation leading to the formation of a
hydroxylamine derivative. The products of the hydroxyl and aromatic N-oxides can
be conjugated with sulfate or glucuronic acid [
18
] .
MDMA is effective in 20-30 min from intake and shows a peak plasma level
after about 120 min with continued effects for up to 4-6 h; plasma half-life is 6-7 h.
Metabolism proceeds by two routes. The principal one involves O-demethylation to
3,4-dihydroxymetamphetamine (HHMA) followed by O-methylation to 4-hydroxy-
3-metoxymetamphetamine (HMMA) and 3,4-dihydroxyamphetamine (HHA) and
subsequent O-glucuronide and sulfate conjugation. The second pathway involves an
N-demethylation to MDA, followed by deamination and oxidation to the corre-
sponding benzoic acid derivative, substantially conjugated with glycine. The MDA
is a metabolite of both MDMA and MDEA [
19
] .
5
Hallucinogens and Psychedelic Substances
These molecules cause significant changes in the perceptual system, producing sen-
sory illusions and inducing a distortion of reality, the sense of space and time, to the
point of hallucination. Natural, synthetic or semisynthetic substances can cause hal-
lucinogenic effects: psilocin, psilocybin, mescaline, and LSD. Hallucinogenic
effects are also created by phencyclidine and ketamine, but these molecules have a
dissociative character.
5.1
Mescaline
Mescaline (3,4,5-trimethoxyphenethylamine) (Fig.
5
) is mainly contained in
Lophophora williamsii peyote
, a cactus native to the deserts of Mexico. Peyote con-
tains an average of about 1.5 % of mescaline. It is often synthetic and looks like a
clear powder with colors ranging from white to brown, depending on purity.
