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Ana González Hernández

Toxicological Chemistry

Erasmus group


The cases of intoxications from illicit
drugs are becoming more frequent, and this supposes a public health problem.
For most of these intoxications there is no antidote, it is important to know
which are the different and characteristic signs and symptoms of these episodes
in order to provide the correct treatment.

Sometimes a clinical observation and a
urine toxicology test are enough to make a diagnosis, but there are some other
laboratory test that, although they may provide more information for the
diagnosis, performing those test is not practical or it’s not worth it. Here,
we can include:

Evaluation of the blood levels
of a drug

Monitoring of vital signs

Changes in blood pressure,
temperature and respiratory frequency

By recognizing which type of intoxication a
patient is suffering, clinician can decide which type of diagnosis test and
treatment is the most accurate



Drug abuse produces alterations in the
functioning of the following neurotransmitters or their receptors: dopamine,
acetylcholine ?-aminobutyric acid, norepinephrine, opioids and serotonin and
therefore originate all the symptomatic effects.

Anticholinergic drugs
antagonize acetylcholine receptors.

Dissociative drugs affect all
transmitter sites.

Opiates act on both opioid and
adrenergic receptors

Psychedelic drugs stimulate
serotonin liberation, and sedative-hypnotic drugs potentiate the ?-aminobutyric
acid receptor.



The stimulation of different
neurotransmitters and receptors leads to different manifestations. According to
what signs and symptoms a patient presents, the doctor can deduce quite
accurately what type of drug is the cause, and provide the correct treatment to
counteract the effects of the intoxication. Since the symptoms and signs of
intoxication can vary, either due to the different doses administered or the
adulteration of the drugs, the symptoms are often misdiagnosed. This fact gets
more complicated if we take into account the interactions that can take place
due to the consumption of multiple drugs, idiosyncratic reactions and mixed
intoxications-withdrawal states.

The neurotransmitters affected by the known
abuse drugs limited. The following diagrams show a biopsychiatric model that
can assist family physicians in the diagnosis and election of a treatment. This
model is based on the functioning of six neurotransmitters.


This essay is focused on drugs of abuse.
Drugs of abuse are those drugs that are taken for non-medical reason (usually
for mind-altering effects). We will make a review of some of the most popular
drugs of abuse


1.     MAIN



Depressant, also called “downers”, are
drugs that lower neurotransmission levels, which is to depress or reduce
arousal or stimulation, in various areas of the brain. In this group we can
find: alcohol, barbiturates, benzodiazepines, cannabis, opioids and miscellaneous.

1.       ALCOHOL

Alcohol is the universal term referred to
ethanol (a low molecular weight hydrocarbon obtained from the fermentation of
sugars and cereals), which is present in alcoholic beverage and is the cause of
ethylic intoxications. Ethanol is rapidly absorbed across the gastric mucosa
and then, across the small intestine, reaching the peak concentration 20-60
minutes after ingestion

The toxic dose of alcohol is 1g/kf and the
lethal dose is 8g/kg. The ethylic intoxication is characterized by physical and
mental impairment, and besides this, alcohols level can be measured in the


Alcohol is a multiple-action of the CNS,
and the depression that it causes is dose-dependent. It can affect multiple
neurotransmisor, but the interaction that causes the representative symptoms of
alcohol intoxication is that with GABA (gamma-aminobutyruc acid), which is and
inhibitory neurotransmitter. This interaction has been proved in studies that demonstrate
that using substances that increase GABA activity (such as GABA-reuptake
blockers and benzodiazepines) the symptoms of alcoholic-withdrawal syndrome
where decreased