Ethanol and Drugs of Abuse Flashcards
define drug abuse
use of drug for non-therapeutic purposes to obtain euphoric mood
define psychological dependence
strong urge to obtain drug to achieve euphoric mood
define physical dependence
state of physiological adaptation to drug
results in withdrawal syndrome
define tolerance
state of physiological adaptation to drug such that progressive higher doses are required to produce the desired effects
alcohol/ethanol was initially a
‘social drug’
what are the 4 therapeutic indication of ETOH?
- irreversible nerve block or tumor destruction
- topical reduction of body temperature
- antiseptic
- early anesthetic agent
what are the effects of alcohol?
disinhibitor & euphoriant
alcohols produces additive effects w/
- benzodiazepines
- barbiturates
alcohol has additive effects through what reward pathway of the brain?
- dopaminergic “reward” pathway in the brain
alcohol increases the synthesis or release of….
this leads to….
- endogenous opioid endorphins
- an increase of dopamine release
in general ethanol acts via
modifying activity of ligand-gated ion channels
with ethanol generally what is inhibited and facilitated?
- inhibited: cations (Na+, K+, Ca++)
- facilitated: anions (Cl-)
alcohol is absorbed via
passive diffusion
the distribution rate of alcohol is proportional to
blood flow
high concentrations of alcohol reach the brain because of
- large amount of blood flow
- ease of membrane passage
alcohol metabolism is rapid through a
high first pass effect
what does the high first pass effect mean?
that more than 90% is metabolized by the liver
the metabolism of alcohol occurs by what 2 enzymes in the liver?
- ADH
- ALDH
ADH: alcohol dehydrogenase
ALDH: aldehyde dehydogenase
what do chronic alcoholics experience?
enzyme induction
chronic alcoholics experience enzyme induction which indicates that
larger amounts of ethanol are required to reach a blood plasma concentration that will produce the desired effects
ETOH is metabolized by
zero order kinetics
what does zero order kinetics mean?
that its concentration independent and a constant amount is metabolized over time
what is a drug that is used to discourage the use of alcohol?
disulfiram (Antabuse)
why is disulfiram (Antabuse) effective in treating chronic alcoholism?
b/c it leads to an accumulation of acetaldehyde in the plasma which can be really painful to the individual
what is the MOA for disulfiram?
it inhibits aldehyde dehydrogenase leading to the increase acetaldehyde
what are the effects of disulfiram?
- flushing
- sweating
- nausea
- tachycardia
methanol uses what enzymes for metabolism?
- ADH
- ALDH
what are the metabolites produced from the metabolism of methanol?
- formaldehyde
- formic acid
what adverse effects are produced by formaldehyde & formic acid?
- blindness
- abdominal and GI disturbances
- acidosis
- respiratory failure
- coma & death
what is the common antidote for methanol poisoning?
alcohol
why is alcohol the antidote to methanol poisoning?
ETOH saturates the acetaldehyde enzyme b/c it has a higher binding affinity than methanol
prevents the formation of toxic metabolites
what are the 6 primary side effects of alcohol toxicity?
- GI
- liver
- pancreas
- cardiovascular
- kidney
- neurological
how is the GI affected by alcohol toxicity?
- bleeding ulcers
- cancer
- gastritis
how is the liver affected by alcohol toxicity?
increased NADH leading to a fatty liver and cirrhosis
how is the pancreas affected by alcohol toxicity?
pancreatitis
how is the cardiovascular system affected by alcohol toxicity?
- hypertension
- tachycardia
- arrhythmias
how are the kidneys affected by alcohol toxicity?
ADH is inhibited increasing diuresis
how is the neurological system affected by alcohol toxicity?
neural atrophy & demyelination
why can BAC be 20-30% higher in females?
- smaller volume of distribution (Vd)
- less First Pass Effect in the liver
what is the most common cause of preventable birth defects?
FAS (fetal alcohol syndrome)
ethanol is considered a ______________ in humans
teratogen
what are the effects of alcohol abuse during pregancy?
abnormalities and retardation of growth and development of the brain and CNS
