Central Nervous System Depressants

1
Central Nervous System Depressants

• Alcohol, GHB, Rohypnol, Barbiturates,
  Benzodiazepines

2
Action of Depressants

• Overall, depressants decrease CNS Activity. This
  may result in the following
• Decreased heart rate, blood pressure,
  respiration. All attributable to muscle
  relaxation.
• Decreased coordination, body temperature,
  sensitivity to pain, general awareness
  reactivity.
• Decreases in Anxiety and Inhibition.

3
Arousal Levels from Depressants

• Normal
• Relief from Anxiety
• Disinhibition
• Sedation
• Sleep
• General Anesthesia
• Coma
• Death

Increasing Dose of Drug
4
Factors Influencing Effects

• Differences between Depressant Types
• - Effective Doses / Lethal Doses
• Amount Consumed
• Combination Effects
• Additive (3 3) 6
• Synergistic (3 3) 12

5
Examples of Depressants

• Alcohol
• Barbiturates
• Benzodiazepines
• Rohypnol
• Gamma hydroxy butyrate (GHB)

6
ALCOHOL
7
CHEMISTRY OF ALCOHOL BEER

• Brewed from a mixture of grains
• Contains 3-6 alcohol by volume
• Ales and malt liquors are 6-8 alcohol by volume

8
WINE

• Made by fermenting the juices of grapes or other
  fruits
• Table wines contain 9-14 alcohol
• Fortified wines (alcohol has been added) contain
  20 alcohol, sherry, port, and Madeira

9
HARD LIQUORS

• Made by distilling brewed or fermented grains.
• Gin, whiskey, brandy, rum, and liqueurs
• Contain 35-50 alcohol

10
Alcohol Facts

• A standard drink is generally defined as 12
  ounces of beer, 5 ounces of wine, and 1.5 ounces
  of 80 proof distilled spirits
• Small amounts (1-2 drinks/day) have protective
  effects on coronary vascular disease and
  myocardial infarction
• For a given amount of alcohol ingested, women
  achieve higher Blood Alcohol Levels.
• The brain achieves a higher alcohol
  concentration, more rapidly than other organs

11
Alcohol Getting in the body

• 20 of initial alcohol is absorbed into the
  bloodstream from the stomach.
• 75 is absorbed through the upper part of the
  small intestine.
• The remaining alcohol enters the bloodstream
  along further along the gastrointestinal tract.

12
Absorption

• Carbonation increases the rate of absorption.
• Food in the stomach slows absorption
• Drinking highly concentrated alcoholic beverages,
  such as hard liquor, slows absorption.

13
METABOLISM

• Rapidly distributed throughout body tissue by
  biological membranes
• Main site of metabolism is the liver
• 2-10 of alcohol is excreted unchanged by the
  lungs, kidneys, and sweat glands
• Rate of metabolism varies among individuals and
  is largely determined by genetic factors.
• General Guideline Body processes appx. 1
  standard drink per hour.

14
Alcohol Getting Out

• Alcohol is metabolized by the liver via the
  enzyme Alcohol Dehydrogenase (ADH) into
  acetyldehyde, which in turn is broken down by
  another enzyme, Acetyldehyde Dehydrogenase into
  acetate, which is then excreted.
• The intermediate product, acetyldehyde, is a
  toxic chemical that can make a person feel quite
  sick, and if it accumulates in the body, intense
  feelings of nausea and illness will result. Hence
  the common sickness people experience after
  drinking a large dose of alcohol.

15
Effects on Specific Neurotransmitters.

• Until recently it was thought that alcohol
  treated all nerve cells equally, simply
  inhibiting their activity by disturbing their
  membrane integrity. It seemed very non-specific.
  However, research has shown that alcohol has very
  powerful effects on at least 2 main receptors.

16
Glutamate and GABA

• Glutamate and GABA are primarily responsible for
  excitatory/inhibitory activity in the brain. When
  the terminals of one cell release GABA onto the
  GABA receptors on the next cell, that cell
  becomes less active.
• Conversely, if Glutamate from one cell lands on
  glutamate receptors on another, that cell will
  become more active. This is how the brain
  maintains the delicate balance between excitation
  and inhibition.

17
Glutamate and GABA

• At the receptor site, alcohol increases the
  suppressive effects of GABA and decreases the
  excitatory effects of Glutamate. These are the 2
  ways alcohol primarily suppresses brain activity.
  
• Its effects on memory can be even more specific,
  since one receptor for glutamate, the NMDA
  receptor, has been shown to play a key role in
  memory formation. This receptor is very
  powerfully inhibited by alcohol and may account
  for the memory deficits that people experience
  after drinking.

18
Dopamine

• Alcohol drinking increases the release of
  Dopamine in these reward centers, probably thru
  the action of GABA neurons, which connect to
  dopamine neurons.
• Dopamine levels increase only while ethanol
  concentrations are RISING, and that it ceases
  once it has leveled off.
• This dopamine rush and its cessation may motivate
  the drinker to consume more alcohol to start the
  pleasure sequence again. The problem occurs
  because once the rush is over, there is still
  plenty of alcohol left in the blood.

19
Alcohol and Brain Cells

• Its highly unlikely that anyone could drink
  enough alcohol in one sitting to directly kill
  brain cells. However, chronic use does have
  damaging effects in some brain areas. Researchers
  have found that if they injected alcohol directly
  into the brain, the cells in that region would
  die.

20
Blood Alcohol Concentration

• The roadside breathalyzer test is actually an
  excellent way of estimating the amount of alcohol
  consumed, even though 95 percent of the alcohol a
  person drinks is metabolized before the body
  excretes it. Only about 5 of the absorbed
  alcohol is eliminated unchanged, in the urine or
  thru the lungs, but is enough to result in
  alcohol breath and the proportion stays constant
  enough to give a very accurate estimate of how
  much alcohol is in the blood.

21
Blood Alcohol Concentration

• Low concentrations of alcohol .03-.05
• Light-headedness, relaxation, release of
  inhibitions, mild euphoria, more social
• Seems like a stimulant in social settings because
  alcohol depresses inhibitory centers in the brain.

22
Blood Alcohol Concentration

• Higher concentrations of alcohol .05-.10
• Emotional instability, with exaggerated feelings
  and behavior
• Impairment of reaction time and fine motor
  coordination
• Legally drunk at .08 in Florida

23
.10-.15

• Loss of peripheral vision
• Smell, vision, taste, and hearing become less
  acute
• Unsteadiness in standing and walking
• Driving is extremely dangerous

24
.15-.30

• Staggering gait
• Slurred speech
• Pain and other sensory perceptions greatly
  impaired
• Unable to function physically or psychologically
  due to pronounced depression of the CNS, muscles,
  and other body systems

25
More than .30

• Stupor or unconsciousness
• Anesthesia
• Death is possible at .35 and above
• Can result from rapid or binge drinking with few
  earlier effects

26
ACUTE EFFECTS

• Reduced physiological sexual response
• Blood vessels near the skin dilate. This causes
  flushing and sweating.
• High doses may impair bodys ability to regulate
  temperature, causing it to drop sharply
  (hypothermia).

27
ACUTE EFFECTS CONTINUED

• Disturbs normal sleep patterns
• Sleep is often light, punctuated with awakenings,
  and unrefreshing
• Alcohol poisoning which can be fatal.
• Due to CNS and respiratory depression or by
  inhaling fluid or vomit into the lungs

28
CHRONIC EFFECTS OF ALCOHOL USE
29
DIGESTIVE SYSTEM

• Cirrhosis of the liver- lose capacity to tolerate
  alcohol, because the cells cannot metabolize it
• Inflamed pancreas- causes nausea, vomiting,
  abnormal digestion, and severe pain- can occur
  after one or two binge drinking episodes. It is
  often fatal!
• Kidney failure
• Nutrition deficiencies

30
CARDIOVASCULAR SYSTEM

• gt2 drinks per day could elevate blood pressure
• Cardiac myopathy- weakening of the heart muscle
• Holiday heart- serious abnormal heart rhythms
  caused by binge drinking.

31
CANCER

• gt3 drinks per day doubles a womans risk of
  developing breast cancer.
• Moderate drinking has been linked to cancer of
  the mouth, throat, and esophagus.

32
MORE CHRONIC EFFECTS

• Lowered resistance to disease
• Menstrual irregularities, in women
• Impotence, and testicular atrophy, in men
• Increased risk of osteoporosis

33
THE BRAIN

• Damages brain cells
• Impairs memory
• Loss of sensation in limbs
• Brain atrophy

34
Effects on Mental Functioning

• 4 Areas where people show deficits.
• Memory Formation
• Abstract thinking
• Problem Solving
• Attention and Concentration
• As many as 70 of people who seek treatment for
  alcohol related problems suffer significant
  impairment of these abilities.
• Heavy chronic drinkers who quit drinking recover
  these abilities partially, but will never fully
  recover

35
Chronic Dangers may result in death

• Alcohol Withdrawal Syndrome The more common of
  two general reactions to the cessation of alcohol
  consumption in an alcoholic. It is characterized
  by physiological discomfort, seizures, and sleep
  disturbances.
• Delerium Tremens The less common of two general
  reactions to the cessation of drinking in an
  alcoholic. It is characterized by extreme
  disorientation and confusion, fever,
  hallucinations, and other symptoms.

36
Delerium Tremens Explanation

• Imagine neurons prevented from firing every day
  by alcohol. A logical response would be for the
  neuron to do whatever it could to fire more
  often. They adapt by increasing receptors that
  stimulate neural firing and decreasing receptors
  that inhibit firing.
• Now take a person who has just stopped alcohol
  cold turkey. All the neurons are very excitable,
  and result in tremendous overexcitation of the
  nervous system. This overexcitation can lead to
  seizures, hallucinations, even death.

37
GHB (Gamma Hydroxybutyrate)

• GHB (Gamma hydroxybutyrate) usually comes as an
  odorless liquid, slightly salty to the taste, and
  sold in small bottles. It has also been found in
  powder and capsule form.
• It is classified as a sedative-hypnotic, and was
  originally developed as a sleep-aid.
• A similar drug, "GBL," is often sold under
  different names and turns into GHB in the body,
  having the same effect.

38
GHB Natural Effects

• Naturally occurring throughout the body.
• Highest amounts in hypothalamus, basil ganglia
• Kidney, Heart, Skeletal Muscle, Fat tissue
• Possible Neurotransmitter
• Precursor Metabolite of GABA
• Dopamine Inhibitor (Temporary)
• Promotes Release of Pituitary Growth Hormone

39
GHB Natural Effects

• Reduces protein break down rates in body
• Used in Muscle building and fat loss.
• Breaks downs into Carbon-dioxide and water
  rapidly (fast metabolism few hours)

40
Physiological Effects

• Anesthetic Effects
• Increased Blood Sugar
• Decrease in Cholesterol
• Slows breathing
• Slight Blood Pressure effects (either direction)
• Slowing of heart rate
• Drop in Body Temperature
• Stimulates mild increase acetylcholine release in
  brain.

41
Dosages

• GHB has a very steep dose response curve compared
  to other depressants.
• GHB comes in a liquid mixture, sometimes making
  dosing difficult based upon concentration.
• A teaspoon or capful by mouth is usually
  considered a normal dose,(.05 1.5 grams) but
  strength can vary from batch to batch. Careful
  users start with half a teaspoon and wait at
  least an hour before deciding whether to take
  more.
• It's hard to find the proper dose with GHB. A
  teaspoon might be perfect one time, but an
  overdose the next time.

42
Onset of Effects

• The effects are usually felt between ten minutes
  and one hour after ingestion. The primary effects
  last about 2-3 hours, but residual effects can
  last up to a whole day.
• The effects may not peak for up to two hours, and
  many overdoses have occurred from people not
  waiting long enough before taking more.
• Don't drive on GHB. One dose can impair motor
  coordination by as much as six drinks of alcohol.
  Also, the effects come on fast and, unlike
  alcohol, cannot be controlled or paced.

43
GHB Psychoactive Effects

• At lower doses GHB has a euphoric effect similar
  to alcohol, and can make the user feel relaxed,
  happy and sociable.
• Higher doses can make the user feel dizzy and
  sleepy, and can sometimes cause vomiting, muscle
  spasms, and loss of consciousness.
• Overdoses will always cause loss of consciousness
  (temporary coma), and will slow down breathing.
  Sometimes, and particularly if mixed with
  alcohol, GHB can slow breathing down to a
  dangerously low rate, which has caused a number
  of deaths.

44
Risks of GHB

• Mixing GHB with alcohol or other depressants is
  extremely dangerous and has caused many deaths
  due to respiratory failure.
• GHB Alcohol compete for same metabolic enzymes
  chemical in liver. GHB wins and blood alcohol
  levels are not able to fall.
• Passing out on GHB by itself is also dangerous
  and potentially life-threatening.
• Regular, daily use of GHB can cause physical
  dependency with harsh withdrawal symptoms.

45
Barbiturates

• Class of Anti-anxiety medication first introduced
  in the 1860s. Derivative of Barbituric Acid.
  First developed by Bayer.
• Effective Sedative-hypnotic agent used to treat
  anxiety, agitation, insomnia.
• Narrow margin of safety and high abuse potential.

46
Barbiturates

• Do not act on a particular receptor, but likely
  increase GABA activity.
• Interfere with reticular activating system,
  limbic system, and motor cortex. May also
  interfere with memory formation.
• Very narrow margin of safety Overdoses are
  prominent. (Depressant scale)

47
Barbiturates

• Abuse includes potential acute and chronic
  intoxication. Mimics drunken behavior in many
  ways.
• Over long periods of time, produces toxic effects
  more life threatening than opiates.
• Also, long term uses produces high tolerance and
  severe dependence (similar to alcohol)

48
Barbiturates

• Three major categories Short, Moderate, and
  Long-acting.
• Examples
• Secobarbital, Short, rapid Reds
• Pentobarbitol Short, Yellows
• Amobarbital Moderate, Blues
• Phenobarbital Long, Purples

49
Benzodiazepines

• Developed as a safer alternative to Barbiturates.
• Acts directly on GABA receptors which inhibits
  several areas of brain in particular the
  reticular activating system, limbic system, and
  motor cortex.
• Like Barbiturates, three major categories are
  Short, Medium, and Long acting.

50
Benzodiazepines

• Examples
• Halcion (Short)
• Ativan (Medium)
• Xanax (Medium)
• Valium (Long)

51
Rohypnol

• Slang or Street Names Roofies, Rophies, Roche,
  Forget-me Pill
• Rohypnol (flunitrazepam) belongs to the class of
  drugs known as benzodiazepines (such as Valium,
  Halcion, Xanax, and Versed). It is not
  approved for prescription use in the United
  States, although it is approved in Europe and is
  used in more than 60 countries as a treatment for
  insomnia, as a sedative, and as a presurgery
  anesthetic.

52
Description of Ingestion

• Rohypnol is tasteless and odorless, and it
  dissolves easily in carbonated beverages. The
  sedative and toxic effects of Rohypnol are
  aggravated by concurrent use of alcohol. Even
  without alcohol, a dose of Rohypnol as small as 1
  mg can impair a victim for 8 to 12 hours.
• Rohypnol is usually taken orally, although there
  are reports that it can be ground up and snorted.

53
Effects of Rohypnol

• The drug can cause profound "anterograde
  amnesia" that is, individuals may not remember
  events they experienced while under the effects
  of the drug. This may be why one of the street
  names for Rohypnol is "the forget-me pill" and is
  used in sexual assaults.
• Other adverse effects associated with Rohypnol
  include decreased blood pressure, drowsiness,
  visual disturbances, dizziness, confusion,
  gastrointestinal disturbances, and urinary
  retention.

54
Benzodiazepines

• Short term effects mimic alcohol effects on
  depressive scale w/ less respiratory depression.
  However, very few lethal overdoses are reported
  involving benzodiazepines alone. Usually a second
  depressant is involved (alcohol)
• No clearly established long-term health
  consequences are associated with use.

55
Tolerance and Withdrawal

• Individuals are able to build up a tolerance to
  both classes of drugs, however they are more
  pronounced in barbiturates.
• Withdrawal, dependence, and abuse are also more
  pronounced with barbiturate use.