Download Chapter 4: ALCOHOL

Chapter 4: ALCOHOL
• Pharmocologically ethyl alcohol is a CNS
depressant.
• Terms like “sedative”, “tranquilizer”, “anxiolytic”,
etc, can be applied to it because it diminishes
environmental awareness, reduces response to
sensory stimuli, depresses cognitive functioning
and spontaneity, and reduces physical activity.
3-Step Process of Alcohol
Metabolism
• Alcohol Dehydrogenase converts alcohol to
acetaldehyde. A coenzyme, nicotinamide adenine
dinucleotide (NAD) is required for activity of this
enzyme.
• The enzyme alcohol dehydrgenase converts
acetaldehyde to acetic acid. The drug disulfiram
(Antabuse) irreversibly limits this enzyme.
• Acetic acid is broken into CO2 and H2O, thus
releasing energy (calories).
Gender Differences In Metabolism
• Women have about 50% less gastric metabolism
of alcohol because they have a lower level of
gastric dehydrogenase enzyme. Result is BAC is
increased about 7% over a man of same weight/
body fat
• Men have greater muscle/ fat ratio. Men thus have
larger vascular dept. because fat gets very little
blood supply. Therefore, alcohol is more diluted in
men.
• Women concentrate alcohol more in the plasma
Kinetic Differences
• The metabolism of alcohol is termed zero order,
that is the metabolism rate is fairly constant for a
given individual and among individuals regardless
of the concentration in the blood.
• Most drugs are metabolized by first order
metabolism. The amount of drug metabolized per
time unit depends on the amount or concentration
in the blood.
Rate of Metabolism
• It takes about an hour to metabolize an
ounce of whisky, a 4oz glass of wine, 12oz
beer, or a pint of 7% microbrew.
BAC
• BAC in most states is .08% to be considered
legally drunk.
Alcohol’s Effects on CNS
• Identifying mechanism of action is difficult
• High dose effect explained by alcohol has a
general depressive action on nerve membranes and
synapses. It dissolves into nerve membranes and
distorts and disorganizes them, similar to a general
anesthetic action.
• New evidence suggests alcohol may both disturb
synaptic activity of various neurotransmitters, as
well as intracellular transduction processes.
Benzodiazepine Treatment
• Use “Bennys” to treat acute withdrawal
because they ameliorate the symptoms and
prevent DT’s and tremors.
• Alcohol is a short acting drug, making it
dangerous to withdrawal from because
existing bodily supplies are rapidly used up.
Substituting a longer acting drug prevents
or suppresses withdrawal symptoms.
Drug Treatment
• Drugs used to decrease consumption, craving, and
maintain abstinence: Disulfiram, Calcium
Carbimide, Naltrexone, etc (p.115).Some work as
alcohol sensitizing agents (makes you sick when
you drink), some work as anti-craving agents,
SSRI’s treat comorbid depression, but little
efficacy shown for treating alcoholism
• Alcohol withdrawal reducing agents:
Benzodiazepines (first choice), Forespeak,
Coniine, Carbamazepine, Chlorpromazine
• Alcoholism is the disease, Alcohol withdrawal is a
symptom of it.
Disease Concept of Alcoholism
• Late 1950’s AMA recognized alcoholism as an
illness.
• Revision in the 70’s defined it as a chronic,
progressive, and potentially fatal disease.
• 1992 def. Characterization includes continual vs.
periodic component, impaired control over
drinking, preoccupation, use despite adverse
consequences, and distortions in thinking (denial)
Comorbidity
• Some models stress the role self-medication
plays in the development of alcoholism.
• Alcoholism is highly comorbid with
depression (30-50% meet criteria for major
depression), anxiety (33%), bi-polar,
antisocial personality, schizophrenic, and
36% are addicted to other substances
Inhalant Abuse
• Chronic use leads to problems such as peripheral
and central nervous system dysfunction, liver/
kidney failure, loss of cognitive and higher order
functioning, gait disturbance and loss of
coordination
• Prenatal effects on infants include ;growth
retardation, facial dysmorphism, and finger/ toe
malformations
• Death is always a possibility
Fetal Effects of Alcohol
• Fetal Alcohol Syndrome (FAS) and Alcoholrelated Neurodevelopmental Disorder (ARND)
• Problems include: CNS dysfunction (low
intelligence, mental retardation, behavioral
abnormalities including hyperactivity and
difficulty with social interaction)
• Facial abnormalities (short nose, wide eyes, etc)
• Other Anatomical Abnormalities (heart defects,
malformed eyes and ears)
• There is no safe level of alcohol intake during
pregnancy established