Alcohol Flashcards
What class of drug is alcohol
sedative hypnotic; CNS depressant
What is the legal intoxication limit in most states
0.08-0.1%
what is the relationship between BAL and probability of getting in a traffic accident
Higher levels of BAL = Higher probability of traffic accident
Describe the Ethyl alcohol molecule
Small
No net charge but strongly polar
Absorbed easily in GI tract
What is the oil/water coefficent of Ethyl
Just high enough to cross BBB but low enough to NOT be stored in fatty tissue
What is the pharmacokinetics of alcohol
Quick Onset
short duration
How is the BAC effected across male and females
Females tend to have higher BAC due to less water volume (ethyl has low fat solubility)
Describe the absorption rate of alcohol
it takes 1 hour for 90% of EtOH to reach the blood stream
what factors can effect the absorption rate of alcohol
Full stomach slows absorption rate
Carbonation speeds absorption rate
How is alcohol metabolized
Rate of metabolism is independent of concentration
90% in liver
10% evaporates via lungs
what is first order kinetics
A constant proportion of drug is removed in a given amount of time so that with a high blood level the amount metabolized is high (most drugs)
what is zero order kinetics
Rate of metabolism is constant over time and independent of concentration (alcohol)
what is the rate of alcohol metabolism
0.25-0.3 oz/hour
What is the main factor that determines alcohol metabolism
activity of alcohol dehydrogenase
What is the difference of alcohol dehydrogenase between men and women
Men have higher amounts of alcohol dehydrogenase
What is the pathway of alcohol metabolism
Ethanol –> Acetaldehyde –> Acetic Acid –> CO2 + H20
What is the pathway of alcohol metabolism
Ethanol –> Acetaldehyde –> Acetic Acid –> CO2 + H2O
what is the rate limiting factor of alcohol metabolism
alcohol dehydrogenase
what is step 1 of alcohol metabolism catalyzed by
alcohol dehydrogenase
what is step 2 of alcohol metabolism catalyzed by
aldehyde dehydrogenase
what is the most likely contributing factor of physiological symptoms of alocohol
build up of acetaldehyde (toxic)
i.e sweating, flushing, nausea
What are gene differences in metabolism
genetic variability in aldehyde dehydrogenase; can result in higher levels of acetaldehyde when drinking
what is phase A of a single drink
Absorption taking place more rapidly than excretion
what is phase B and C of a single drink
absorption tapers off and excretion starts to lower BAL
what is phase D of a single drink
absorption is complete and alcohol is eliminated at a constant rate
What is cirrhosis
severe hardening and contraction of the liver
what does chronic drinking do to the liver
reduces rate at which the liver forms glucose, oxidizes fats, and releases complex fats; fat accumulates causing cell death and fibrosis
what is the lethal dose of alcohol
0.5% BAC
why is it hard to reach the lethal dose of alcohol hard reach
physiological safe guards:
0.12% –> vomiting
0.35% –> Pass out
what are the pharmacodynamics of alcohol
effects membrane fluidity (more fluid) which interrupts channel activity and inhibits movement of Na and K ions
How does alcohol effect neuronal activity
increases GABA functioning (positive allosteric modulator of GABA-A)
Decreases glutamate functioning
What happens with greater GABA activity
inhibition of neurons
greater Cl- influx
what happens with less glutamate activity
less excitation of neurons
What are opioid peptides
Alcohol causes release of alcohol endogenous opioid (endorphins) which acts on mu-opioid receptors to limit GABA release on VTA which increases dopamine onto the NAc
How does alcohol act on serotonin receptors
alcohol acts on 5HT3 receptors to depolarize VTA terminals leading to increased DA release
what are the physiological effects of alcohol
vasodilation, increasing heat loss, decreases levels of ADH (dehydration), increases stomach acid (hunger)
what are the psychological effects of alcohol
CNS depressant
more assertive
relieves tension
reduces anxieties
enhances social interaction
why is alcohol no longer used as an anesthetic
slow metabolism
low therapeutic index
slows blood clotting
what are the three mechanisms of overall depression of the CNS
reduces release of inhibitory NT
reduces firing of inhibitory pathways
decreases excitatory NT
what is interesting about the peak effects of alcohol and BAC
effects of alcohol are more serious when BAC is rising than when falling
what does chronic alcohol use due to the brain
enlargement of ventricles and changes in cortex surface
what is wernike-korsakoff syndrome
lack of thiamine (B12)
psychosis characterized by inability to remember recent events and learn new information
describe tolerance to alcohol
upregulation of NMDA receptors
Downregulation of GABA
behavior compensation
what is hyperexcitability
upregulation of glutamate receptors with chronic exposure to alcohol
what is a hangover related to
high levels of acetaldehyde
lack of sleep
dehydration
low blood sugar
what are the four stages of alcohol withdrawal
minor symptoms
alcoholic hallucinosis
withdrawal seizures
delirium tremens
what are genetic polymorphisms that were identified to increase risk of alcoholism
GABA-a receptors
muscarinic acetylcholine receptors
D2 and D4
what is disulfiram
aversion based pharmacotherapy
inhibits aldehyde dehydrogenase to allow acetaldehyde accumulation
what are some genetic predispositions for alcohol abuse
altered levels of ADH or ALDH
5-HT transporter (more rapid uptake, decreasing levels of serotonin which minimizes effect of alcohol in NAc)
GABA-A receptor (decrease effects of alcohol on balance, speech, and coordination)
