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 Alcohol-related 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