Week 3 (everything else...) Flashcards
(230 cards)
What is the definition of substance intoxication?
recent ingestion of a substance
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clinically significant problematic behavior and/or psychological changes attributable to the physiological effects of the substance on the CNS
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fits an intoxication syndrome profile
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not attributable to other causes
What is the definition of substance withdrawal?
prolonged use of a substance
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cessation of the substance and specific signs/symptoms associated with cessation
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signs/symptoms cause clinically significant distress or impairment
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symptoms not attributable to another cause
What factors influence intoxication and withdrawal?
timing (chronic vs. acute)
route of administration
duration of action/potency
metabolism
mechanism of action
What is the mechanism of alcohol intoxication?
interferes with membrane fluidity and affects function of ion channels and receptors
enhances nicotinic acetylcholine channels, GABA-A receptors, and increased inhibition of glutamate receptors and voltage-gated calcium channels
What are the symptoms of alcohol intoxication?
slurred speech
incoordination
unsteady gait
nystagmus
impaired memory and concentration
stupor
coma
What are the symptoms of alcohol withdrawal?
autonomic instability
nausea
vomiting
anxiety
sweats
hallucinations
tremor
headache
disorientation
What are the four stages of alcohol withdrawal?
autonomic nervous system instability (occurs 6-48 hours into withdrawal)
seizures (occurs 12-48 hours into withdrawal)
hallucinosis (arises 12-24 hours into withdrawal and lasts up to 3 days)
delirium tremens (arises 3-7 days into withdrawal)
What is ANS instability in alcohol withdrawal? What causes it?
insomnia, tremor, anxiety, agitation
GI distress, headaches, diaphoresis, palpitations
cause: surge in catecholamines that were suppressed by presence of alcohol
What type of seizures are associated with alcohol withdrawal? What causes them?
generalized tonic-clonic seizures
cause: decreased GABA-A transmission, increased glutamate NMDA receptor signaling
What types of hallucinations are associated with alcohol withdrawal? What causes them?
typically visual hallucinations with full orientation
cause: hypothesis is that it is related to increased dopamine signaling
What is delirium tremens? Who is at high risk for this?
the final stage of alcohol withdrawal in some cases
leads to delirium, perception changes, diaphoresis, agitation
higher risk: sustained use prior to withdrawal, history of delerium tremens, comorbid illness, withdrawal signs when alcohol is still in system
mortality is 15%
What are the causes of mortality associated with delirium tremens?
cardiovascular or respiratory collapse
What is the mechanism of action of sedatives, hypnotics, and CNS depressants?
agonism of the GABA-A receptor (which is coupled to a chloride ion channel)
What is the difference between mechanism of barbituates and benzodiazepines?
benzodiazepines: increase frequency of GABA-A chloride channel opening (plateaus)
barbituates: increases duration of GABA-A chloride channel opening (risk of toxicity)
What are the symptoms of sedative/hypnotic/CNS depressant toxicity?
similar to alcohol and is dose dependent
small doses: motor incoordination, impaired cognition
high doses: impaired gait, speech, nystagmus, coma/death
What are the symptoms of sedative/hypnotics/CNS depressants withdrawals?
autonomic hyperactivity, tremor, nausea, vomiting, insomnia, perceptual changes, anxiety, seizures, delirium
Which benzodiazepines carry the greatest risk of withdrawal symptoms?
ones with short half-lives (temazepam, lorazepam, alprazolam)
What is the mechanism of action of cocaine?
it inhibits the reuptake of dopamine (via dopamine reuptake transporter 1) into the presynaptic neuron
it also affects reuptake of norepinephrine and serotonin
What is the mechanism of action of amphetamines?
two mechanisms:
causes release of dopamine from vesicles in the presynaptic neuron into the cytosol
reverses the flow of dopamine reuptake transporter 1 (increases synaptic dopamine)
What parts of the brain do cocaine and amphetamines act on?
ventral tegmental areas (nucleus accumbens) and prefrontal cortex
What are the symptoms of stimulant withdrawal?
dysphoric mood, depression, fatigue, vivid/unpleasant dreams, hypersomnia, low energy, increased appetite, psychomotor changes, cognitive slowing, suicidal ideation
What are the symptoms of stimulant intoxication?
tachycardia, mydriasis, hypertension, perspiration, chills, nausea, vomiting, anorexia, psychomotor agitation or increased energy, aggression, increased libido, cardiac arrhythmias, seizures, chest pain, bruxism, decreased need for sleep, dyskinesias, dystonias, psychosis, bruxism, delirium
What is the mechanism of action of hallucinogens?
variable
some are agonists at the serotonin 2A receptor
MDMA affects serotonin and monoamines system
PCP and ketamine antagonize the glutamate NMDA receptor
What are the symptoms of PCP intoxication?
dissociation, depersonalization, derealization, vertical nystagmus, hypertension, numbness or decreased pain responses, ataxia, dysarthria, rigidity, seizures, severe aggression