Depressants

1
Depressants

• L. Scheffler

2
Depressants

• Depress the central nervous system by interfering
  with the transmission of neural impulses in the
  nerve cells (neurons)

3
Effects of Depressants

• Slow down bodily functions especially motor
  activity and mental activity
• Low doses
• Feelings of calm and reduced anxiety
• Induced sleep
• Large doses
• Loss of consciousness, coma, death

4
Alcohol

• 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

5
Alcoholism

• 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

6
Alcohol Consumption

• Short term effects
• Relaxation, confidence, and increased sociability
• Dialation of blood vessels leads to feelings of
  warmth
• Impaired judgment
• Lengthened neural response time

7
Alcohol Consumption

• 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

8
Synergistic Effects of Alcohol

• 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
• When taken with aspirin it increases the
  likelihood of stomach bleeding

9
Alcohol Withdrawal

• Sudden discontinuation of alcohol by heavy
  drinkers leads to withdrawal symptoms including
• Delirium
• Tremors

10
Legal limits for driving

• 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.

11
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 Number of units men Number of units 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
1 unit 280 cm3 of beer Glass of wine Shot
of liquor
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
12
Alcohol detection

• Breathalyser tests
• Reduction of potassium dichromate to Cr3 ion
• Fuel cell where alcohol is oxidized to produce an
  electric current
• Infrared spectroscopy- intoximeter
• Gas Chromatography

13
Chemical Breathalyzers

• 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.

14
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
•  

15
Other Depressants

• Certain medicines known as antidepressants are
  used to treat anxiety, stress, and clinical
  depression
• These include
• Diazepam (Valium)
• Nitrazepam
• Fluoxetine hydrochloride (Prozac)

16
Fluoxetine Hydrochloride (Prozac)

• 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.

17
Tranquilizers

• 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

18
Tranquilizers

• Tranquilizers are often temporarily prescribed
  for people facing high stress or anxiety.
• Valium
• Xanax

• These drugs are usually 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.

19
Xanex A Common Tranquilizer

• Xanex is a common tranquilizer prescribed for
  persons suffering from acute anxiety. Prolonged
  use can lead to addiction

The Chemical structure of Xanex
20
Halcion

• Halcion is a trade name for a type of compounds
  known as a benzodiazopine. It is similar in
  structure to other tranquilizers

Halicon is a commonly prescribed sleeping
medicine
21
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.

22
Some Barbituates

• 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.

Barbituic Acid
Sodium pentathol