Transcript Option D4 Depressants

Depressants
Depressants
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Depress the central nervous
system by interfering with the
transmission of neural impulses in
the nerve cells (neurons)
Effects of Depressants
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Slow down bodily functions especially
motor activity and mental activity
Low doses
– Feelings of calm and reduced anxiety
– Induced sleep
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Large doses
– Loss of consciousness, coma, death
Alcohol
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Ethanol is the only common
alcohol that can be consumed.
Other common alcohols such as
methanol and isopropyl are much
too toxic.
Alcohols are used as antiseptics
for injections and to harden skin
Alcoholism
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Prolonged consumption of alcohol
leads to both psychological and
physiological dependence
Alcoholism also results in
– Violent antisocial behavior
– Social costs to families
– Safety issues especially road
accidents
Alcohol Consumption
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Short term effects
– Relaxation, confidence, and
increased sociability
– Dialation of blood vessels leads to
feelings of warmth
– Impaired judgment
– Lengthened neural response time
Alcohol Consumption
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Long term effects of heavy
drinking
Cirrhosis of the liver and liver
disease
Coronary heart disease
High blood pressure and strokes
Dementia
Miscarriage
Fetal abnormalities and fetal
alcohol syndrome
Synergistic Effects of
Alcohol
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Ethanol can interact with other drugs,
often enhancing their effect, because it
inhibits the functioning of the central
nervous system
The synergistic effect can be fatal when
alcohol is taken with certain drugs
including
– Benzodiazepines
– Narcotics
– Barbituates
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When taken with aspirin it increases the
likelihood of stomach bleeding
Alcohol Withdrawal
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Sudden discontinuation of alcohol
by heavy drinkers leads to
withdrawal symptoms including
– Delirium
– Tremors’
Legal limits for driving
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All states in the US and many
countries have established
0.08% blood alcohol as the legal
limit for driving.
After drinking the concentration
of alcohol in the blood increases
as the alcohol is absorbed and
then gradually declines.
Legal limits for driving
Estimates of the alcohol consumption needed to
exceed the legal limit of 80 mg per 100 cm3 of
blood for an average adult.
Time taken for
drinking in
hours
1 unit
= 280 cm3 of beer
= Glass of wine
= Shot of liquor
Number of units Number of units
men
women
1
4.0
2.8
2
5.0
3.5
3
6.0
4.2
4
6.5
4.5
5
7.5
5.2
Values are based on an average adult male weighing 150 pounds. Unit values
For women are somewhat less due to a lower body mass and lipid distribution
Alcohol detection
Breathalyser tests
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Reduction of potassium dichromate
to Cr3+ ion
Fuel cell where alcohol is oxidized to
produce an electric current
Infrared spectroscopy- intoximeter
Gas Chromatography
Chemical Breathalyzers
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The dichromate ion, Cr2O72-, has an orange color
while chromium (III) ion, Cr3+, is green.
By determining the level of green color present one
can determine the ethanol concentration..
The ethanol absorbed by the dichromate solution can
be calibrated against blood alcohol levels
The reaction is somewhat time dependent, therefore
it is necessary to compare colors rather than titrate
the solution to an endpoint.
Chemical Breathalyzers
Alcohol chemical breathalyzer tests employ a
chemical colorimetric test to ascertain alcohol
blood levels.
This test is based on the fact that primary
alcohols such as ethanol are oxidized by acidified
potassium dichromate as follows
3 C2H5OH + 2 Cr2O72- + 16 H+  3 CH3COOH + 4 Cr3+ + 11 H2O
Other Depressants
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Certain medicines known as
antidepressants are used to
treat anxiety, stress, and
clinical depression
These include
– Diazepam (Valium)
– Nitrazepam
– Fluoxetine hydrochloride
(Prozac)
Fluoxetine Hydrochloride
(Prozac)
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Prozac is an example of
the selective serotonin
reuptake inhibitor (SSRI)
SSRIs work by preventing
neurons (nerve cells) from
pulling in the serotonin that
is floating in the space
between neurons. This
allows more serotonin to
build up and improves
communication between
the neurons.
Tranquilizers
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Valium
Xanex
Nitrazepam
• Tranquilzers depress
the nervous system
responses but do not
address the underlying
problems.
• They are used to
sedate people in the
short term but can be
very addictive
Tranquilizers
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Tranquilizers are often
temporarily prescribed
for people facing high
stress or anxiety.
Valium
• These drugs are usually
Xanax
prescribed for brief time until
counseling and psychotherapy
can be put in place.
• They are occasionally used as a
pre-medication before surgery.
• Prolonged and over use of
tranquilizers results in drug
dependence.
Xanex – A Common
Tranquilizer
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The Chemical structure of
Xanex
Xanex is a common
tranquilizer
prescribed for
persons suffering
from acute anxiety.
Prolonged use can
lead to addiction
Halcion
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Halicon is a commonly
prescribed sleeping medicine
Halcion is a trade
name for a type of
compounds known as
a benzodiazopine. It
is similar in structure
to other tranquilizers
Barbituates
• Barbiturates are short acting, and include
pentobarbital, secobarbital, and amobarbital.
• Affect the cortex and create a state similar to
alcoholic intoxication in large doses.
• Extremely dangerous when mixed with alcohol
or other drugs.
• A person in withdrawal suffers anxiety,
agitation, loss of appetite, nausea and
vomiting, sweating, a fast heartbeat, tremors,
and cramps.
• These symptoms can escalate to convulsions,
delirium, and hallucinations.
Some Barbituates
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Barbituic Acid
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Sodium pentathol
Barbiturates have
been known since
1864 when Dr. A.
von Bayer
synthesized
barbituric acid.
In 1903, barbital
was introduced as a
hypnotic for routine
medicinal use.