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81 Cards in this Set

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Most widely used centrally acting drug known to man and a widely used industrial solvent?
ethanol
How high can yeast fermentation levels of ethanol reach?
15%; get higher percentage with distillation
3 special physical properties?
1. infinitely soluble in polar and non-polar solvents
2. low molecular weight
3. cannot be ionized
commercial beers
wines
fortified wines (sherry...)
distilled spirits

What is the percent ethanol?
4%-10%
11%-14%
14%-20%
30%-60%
How much ethanol is usually consumed in a standard drink
10-15g
What water compartment is alcohol distributed to?
total body water
--> approx blood level by ingested dose and weight
How is it absorbed?
most in duodenum
a lot in stomach
-gastric emptying may be rate-limiting
Why are blood levels higher in women than in men following an equal dose
some metabolism by dehydrogenase in stomach wall in males, less in females
Over 90% of ingested ethanol is eliminated by metabolism in the ...
liver
Major metabolic pathway
alcohol --> oxidation by ADH (w/ NAD)--> acetaldehyde --> oxidation by aldehyde dehydrogenase (w/ NAD) --> acetate
Minor metabolic pathway
CYP450 (CYP2E1) --> acetaldehyde
acute exposure slows metabolism of other drugs metabolized by CYP2E1; chronic exposure inc CYP2E1
What happens to the acetate?
converted to Acetyl CoA --> citric acid cycle (w/ CoA and ATP) --> CO2, H2O, and CALORIES!
What is the maximum rate of ethanol oxidation by alcohol dehydrogenase limited by?
NAD
What type of kinetics is exhibited?
zero-order (at blood levels excess of .1 mg/ml)
--> constant amt of ethanol eliminated per unit time (rather than constant fraction)
What is the average metabolic rate?
7 grams.hour
(one shot takes 2 hrs to be cleared)
What inhibits Alcohol dehydrogenase?
fomeprazole
What is fomeprazole?
a drug used to delay metabolism of toxic alcohols (methanol, ethylene glycol) that have toxic metabolites
Is ethanol a strong drug?
no, it's weak--> many grams must be taken to induce an effect --> places heavy burdern on elimination system
Ethanol metabolism alters redox potential from inc NADH:NAD ratio, what are the effects of reduced NAD?
fatty acid synthesis inc
fatty acid oxidation dec
plasma FFAs inc
TG accumulate in liver
(all at low non-intoxicating levels)
What does ethanol do to the GI tract?
stimulates gastric acid secretion--> pain in peptic ulcers, inc ulcer formation
Ethanol causes peripheral vasoconstriction or vasodilation?
dilation --> flushing, feel warm --> loose body heat --> hypothermia in cold weather
What does the vasodilation do to the sympathetic nervous system?
causes tachycardia
what are heart benefits of low doses of ethanol?
cardioprotective from dec LDL
reduces risk of ischemic (not hemorrhagic) stroke
What is the primary pharmacodynamic effect of ethanol and how is manifested?
CNS depression; intoxication
What causes the euphoria?
inc release of DA (by disinhibition) in nucleus accumbens --> activates "reward" pathways --> drives further ethanol consumption
What is the legal limit to drive in most states?
1 mg/mL (~20 mM)- CNS effects are related to blood concentrations
What does ethanol do to ADH
inhibits it by inhibiting supraoptic and paraventricular neurons in hypothalamus --> diuresis, dehydration
What does ethanol do to LHRH?
acts at cannabinoid CB-1 receptors --> release of endocannabinoids --> dec LHRH release in hypothalamus --> dec reproductive function
What is the mechanism of action of ethanol?
disrupts neuronal membrane receptors and dec firing
1. inhibits glutamate NMDA activated Ca current --> dec synaptic transmission
2. potentiates GABA mediated inc in Cl conductance
3. enhances sedative effects of adenosine at A1 receptors
mild euphoria
increased reaction time
impaired judgement
increased risk of accident
below 1 mg/mL
irregular gait
ataxia
confusion
slurred speech
elation/euphoria w/ impaired cognition
sedation
1-2 mg/mL
emesis
stupor/severe sedation
anesthesia
respiratory depression
2-4 mg/mL
coma
4-5 mg/mL
death by respiratory depression
>5 mg/mL
5 ways to manage acute ethanol intoxication?
What should you avoid?
1. gastric lavage
2. maintain cardiopulmonary status, temp, acid-base
3. fluids for dehydration
4. antacid or histamine H2 antagonist to dec gastric irritation
5. thiamine and glucose

avoid tx w/ stimulants or other CNS depressants
What can cause extreme toxicity, metabolic acidosis, blindness and death in large quantities?
methanol
How is methanol metabolized?
methanol --> oxidation by alcohol dehydrogenase (w/ NAD) --> formaldehyde
What causes the blindness w/ methanol?
formaldehyde at retina (high local activity of retinol dehydrogenase)
What causes the methanol acidosis?
formic acid formation from formaldehyde
How do you treat methanol poisoning?
1. support if depression present
2. correct acidosis
3. give ethanol or fomeprazole to retard formation of formaldehyde
Are higher alcohols more or less potent than ethanol as CNS depressants?
more
How does anti-freeze work towards intoxication
ethylene glycol is potent CNS depressant
1. oxidation product glycoaldehyde is toxic to kidney -> renal failure and death from uremia
2. secondary product glycolic acid -> metabolic acidosis
How do you treat ethylene glycol poisoning?
fomeprazole
How much alcohol is assoc with significantly reduced risk of cardiac infarction for men?
1-2 drinks per day; 3-7 drinks per week
What was the result of the randomized trial conducted to show reduction in CV disease with moderate daily alcohol intake?
no such trial
What is chronic alcohol use associated with
inc hypertension
cardiac arrhythmias
stroke
Give an operational definition of alcoholism
continued consumption is necessary to prevent onset of withdrawal sx
Is the dependence physiological or psychological?
both
How much of the US suffers from alcoholism
at least 2%
Are persons who are relatively insensitive to the intoxicating actions of alcohols more or less likely to become alcoholics than highly sensitive persons
more likely
bouts of severe intoxication for 1-4 days; abstinence for days
binge drinker
continuous slow rate of consumption; rarely wildly intoxicated; seldom abstinent for more than a few hours
continuous drinkers
What contributes to tolerance?
partly metabolic; also adaptations in CNS pathways
alcohol induces CYP450 enzymes- how does metabolism in alcoholics differ?
up to 50% of ethanol may be metabolized by CYP2E1; inc metabolism
How does metabolism of other drugs that use CYP450 enzymes differ in alcoholics?
abstinent alcoholic- inc metabolism of those drugs
presence of alcohol- dec metabolism of those drugs
What is pharmacodynamic tolerance?
Cross tolerance w/?
Less tolerance to?
dose necessary to produce intoxication increases with constant use; cross tolerance with other CNS depressants (barbituates; general anesthetics; less tolerance to acute lethal effects)
How long do the true withrdawal sx (abstinence syndrome) last upon cessation of alcohol consumption by alcoholics?
start at 12-24 hrs after last drink; last 5-7 days
What sx are included in withdrawal?
tremors; hyper-reflexia; sweating; muscle cramps; vomiting
visual hallucinations, delirium tremens (DT's)
hyperthermia, CV collapse
Grand Mal seizures
When do DTs usually show up?
day 3 or 4
Name other neural effects of chronic ethanol
1. peripheral neuropathy, pellagra: paresthesia, dec DTRs
2. Wernicke's encephalopathy
3. Korsakoff's psychosis
4. Cerebellar degeneration
nicotinic acid deficiency
pellagra
thiamine deficiency
Wernicke's encephalopathy
partial paralysis of eye movements
nystagmus
ataxia
disorientation
Wernicke's encephalopathy
memory loss
confusion
confabulation
Korsakoff's psychosis
ataxia and intention tremor
cerebellar degeneration
What does chronic ethanol exposure do to the liver
1. fat accumulation
2. acetaldehyde accumulation
3. induces CYP2E1
--> necoris and fibrosis --> cirrhosis --> liver failure
What does acetaldehyde do in the liver?
1. inc lipid peroxidation
2. damages mito and cell membranes
3. depletes glutathione
4. depletes vitamins and metals
5. dec transport and secretion of proteins
Why is heavy drinking associated with decreased appetite?
high caloric content
How does ethanol cause pancreatitis?
pancreatic hypersecretion
Acute ethanol drug interactions?
inhibits metabolism of drugs by P450
chronic ethanol drug interactions?
induces CYP2E1 --> inc metabolism of acetaminophen (--> hepatotoxic metabolites), halothane
How sure are we that maternal consumption of ethanol during pregnancy is teratogenic?
unequivocally associated
Name some effects of fetal alcohol syndrome
small head circumference
low IQ
low body weight
impaired immune system
Is fetal alcohol syndrome dose dependent?
heavy drinking is required for full syndrome, but even lower levels result in significant effects on brain and body development
How do you treat alcohol withdrawal syndrome?
1. benzodiazepine (diazepam) to dec seizures
may use lorazepam or diazepam i.v.
may use carbamazepine for seizures
2. fluid and electrolyte supplementation w/ vitamins
Name 3 pharmacologic approaches to maintain alcohol free state in alcoholics
disulfiram (antabuse)
naltrexone
acaprosate
inhibits aldehyde dehydrogenase -> acetaldehyde accumulation -> cutaneous vasodilation, nausea, vomiting, syncope (from hypotension), misery
sometimes hepatitis
antabuse
Which should only be used in conjunction with counseling?
antabuse- aversion therapy
an opiate antagonist, reduces reinforcing effects of ethanol; dec relapses
naltrexone
NMDA and GABA-A receptor modulator; reduces unpleasentness of abstinence, reduces cravings, relapses
acamprosate
which is more effective- acamprosate or naltrexone?
acamprosate