Drugs of Abuse Flashcards
*hallmark of drug abuse?
compulsive drug use
drug abuse definition
- use of drugs without medical approval for euphoria and reward
- drug use in a manner that is detrimental to health and well being
*what is physical dependence?
what are 2 symptoms of physical dependence?
-when you need drug for normal physiological functioning
- development of tolerance (pharmacokinetic-changes in metabolism or pharmacodynamic-adaptations to presence of drug)
- withdrawal syndrome - symptoms are opposite of effects drug would usually produce
*what is physiological dependence?
ADDICTION
-compulsive drug use to induce pleasure or escape from reality despite negative consequences
HIGH RISK OF RELAPSE**
RR of 1=
RR of 5=
1-non addictive
2-highly addictive
mesolimbic dopamine reward system
- activated when?
- molecular targets?
- reward pathway - addictive drugs activate this system
- G-proteins
- inotropic receptors
- DA transporters
- path begins at the ventral tegmentum (VTA) - where all the DA hang out and activates the
- ->Nucleus accumbens (MAIN)
- ->prefrontal cortex
- ->amygdala
- ->hippocampus
How do opioids and THC affect the mesolimbic dopamine reward system?
Inhibit GABA receptors (g-proteins) which stimulates DA neurons to secrete more shit.
How do benzos, nicotine, ethanol affect the mesolimbic dopamine reward system?
bind to GABA_A (Cl channels?) ionotropic receptors = shut down GABA neuron = stimulation of DA neuron
How do cocaine, amphetamine, ecstasy affect the mesolimbic dopamine reward system?
blocking of DA transporters = accumulation of DA in target synapses
CNS depressants and Sedatives/hypnotics RR?
RR=3
Alcohol RR?
Ethanol
RR=3
Benzodiazepines RR?
Diazepam, alprazolam, flunitrazepam
RR=3
Barbiturates RR?
Pentobarbital
RR=3
gamma-hydrocybutyric acids (GHB) RR?
RR=3
ETOH effects @ high doses?
sedative and sleep
ETOH metabolism
-where?
Excretion where?
**90% liver
10 GI tract
**-excreted kidneys and lungs
ETOH metabolism
-which enzymes?
- Alcohol dehydrogenase (ADH)—ETOH to aldehyde
- Microsomal ethanol oxidizing system (MEOS)
- Aldehyde dehydrogenase (ALDH)— aldehyde –> acetate
**Elimination of ETOH follows what kinetics?
zero-order == depends on concentration of enzymes
What is rate limiting factor in ETOH metabolism/elimination?
ADH saturation is rate limiting bc zero order elimination = not dependent on time and concentration of ETOH
WHich enzyme system is activated to metabolize ETOH with chronic use?
Microsomal ethanol oxidizing system (MEOS)
What drug to give to treat methanol and ethylene glycol (anti-freeze) consumption?
give fomepizole - inhihibits ADH
Why is methanol toxic?
-converted to formaldehyde and oxalic acid by ADH - this is why we use fomepizole to block ADH
-formaldehyde is toxic to optic nerve and = metabolic acidosis
oxalic acid has kidney, lung, and CNS toxicity and = metabolic acidosis
**What drug to give to discourage alcoholics from drinking ETOH? WHY?
**-give Disulfiram - inhibits aldehyde dehydrogenase ALDH (second step of ETOH metabolism)
-results in high levels of aldehyde = unpleasant facial flushing, nausea, vomiting, dizziness, headache
What is disulfram used for?
blocks ALDH whcih causes accumulation of aldehyde in alcoholics who drink a lot of ETOH = they get sick when they drink
Males ETOH vs female ETOH effects:
same amount in females = greater blood alcohol bc less Vd (smaller/less water) and decreased first pass metabolism
ETOH MOA?
1) potentiates the effects of gamma-aminobutyric acid (GABA) at GABA_A receptors (INHIBITORY) = increased Cl ion flux and neuronal hyperpolarization
2) inhibits NMDA receptors (excitatory)
ETOH effects on glutamate activates NMDA receptors-
- what is part of NMDA functions?
- what does this translate to with ETOH?
- NMDA –> cognitive function, learning and memory
- relates to ETOH related memory loss = BLACKOUTS
- long term ETOH use results in?
- what does this contribute to?!
up-reg of NMDA receptors =====> CONTRIBUTES TO WITHDRAWAL SIGNS AND SEIZURES!!!!!!!!!
ETOH organ system effects?
Low dose
High dose?
low=excitation, loss of inhibitions, euphoria follwed by impaired judgements and reaction time; slurred speech and ataxia - intoxication or drunkeness
high=drowsiness, amnesia, unconsciousness (blackout) respiratory depression
What drugs does ETOH interact with? effects?
other CNS depressants (barbs, benzos, marijuana)
-sedative effects of all ingested are additive = potentially fatal
- Wernicke Korsakoff Syndrome
- another name for this condition?
- what is it?
- “wet-brain” or “alcoholic encephalopathy”
- neurological condition associated with thiamine B1 deficiency due to excessive ETOH intake
*Symptoms of Wernicke Korsakoff syndrome?
1) occular disturbances - nystagmus and paralysis of EOM
2) Changes in mental state - confusion cognitive defects (execute function)
3) memory impairment - amnesia
4) movement difficulties- ataxia, apraxia
Fetal Alcohol syndrome (FAS)
- what are signs of FAS?
- how much alcohol causes FAS?
- mental retardation, hyperactivity, antisocial behavior
- no safe level of alcohol intake
most common cause of preventable birth defects?
alcohol - FAS!