cocaine Flashcards
Stimulants
Psychoactive drugs producing a
temporary increase in mental function
Psychostimulants
Alertness, wakefulness, and
locomotion
Psychomotor stimulants
Cocaine, amphetamines, caffeine,
nicotine
Cocaine Primary psychoactive component has
moderate bioavailability by
oral
administration
Cocaine is sensitive to
acid hydrolysis
Coca leaves traditionally chewed with lime
to
decrease acid hydrolysis in the GI
cocaine administered via
oral, IV, or intranasal routes
cocaine is Susceptible to breakdown by
heating
cocaine Can be precipitated by heating with
baking soda - crack cocaine
Freebase and crack cocaine delivered by
inhalation
Cocaine is purified by
acid-base
extraction
Illicit cocaine is purified by
partially
drying leaves
Inhalation (smoking) or intranasal (snorting)
result in
in rapid access to the CNS
Half-life in circulation
30-90 minutes.
cocaine Metabolized by
esterases, CYP450 in liver
Cocaethylene is an
active metabolite formed in the presence of alcohol – longer lasting than cocaine and greater cardiotoxic effects.
Methylecgonidine
produced by heating of cocaine and is detectable in urine
Cocaine is amphipathic – meaning it has
both hydrophilic and lipophilic nature
Cocaine is amphipathic Subsequently cocaine is very rapidly absorbed
across the BBB and measurement of cocaine in circulation does not effectively convey the psychoactive levels
Inhalation and intranasal admin both result in
rapid uptake into brain and pronounced psychoactive effects
Rapid uptake into brain and short duration of ‘high
(5-30 minutes) thought to contribute to addictive potential
Effects of cocaine “positive” (7)
Euphoria
Increased alertness
Increased self-confidence
Increased sociability
Heightened sexual interest / performance
Motor stereotypies
Anorexia
Effects of cocaine “negative” (9)
Dysphoria
Irritability, hostility, anxiety
Psychosis
Impulsivity
Increased heart rate
Increased blood pressure
Hyperthermia
Seizures
Stroke / Intracranial haemorrhage
Psychomotor stimulation (7)
locomotor
hyperactivity
head bobbing,
pacing,
repetitive rearing,
excess grooming.
compulsive activities such as obsessive cleaning, sorting, organizing
Animal models
Animal models will rapidly acquire self-administration of cocaine
Cocaine administration causes
hyperactivity in rodents – simple measurement of intoxication
Animals will self-administer to the
point of
personal neglect, anorexia, and increased mortality
Cocaine is an
SNDRI
SNDRI
serotonin, norepinephrine, and dopamine reuptake inhibitor)
Cocaine blocks neurotransmitter reuptake such as at the
dopamine transporter (DAT).
Cocaine blocks neurotransmitter reuptake such as at the
dopamine transporter (DAT) This leads to accumulation of
neurotransmitters in the synapse and excessive downstream signalling.
At elevated doses cocaine blocks (N)
Na+ channels and can be used as a topical anaesthetic
Cocaine Also causes decrease in
monoamine synthesis through presynaptic autoreceptors.
Tolerance
Cocaine tolerance develops acutely and transiently
Subjective and cardiovascular effects develop tolerance
quickly
- Intermittent use produces
sensitization rather than tolerance
In animal models Continuous infusion via minipump results in
tolerance to the effects of cocaine
Daily use (intermittent) sensitizes the
psychomotor and reinforcing effects
Both animals and humans show
cross-sensitization to other stimulants (esp. amphetamines)
Withdrawal
No medically serious withdrawal syndrome develops with cocaine use
- Three phases observed in binge users of cocaine
- Crash (15-30 minutes following final dose)
- Withdrawal (hours-days after final dose)
- Extinction
Binge use refers to
episodic use for extended periods (hours or days) without interruption (or sleep)
Cocaine crash (7)
Dysphoria
agitation
anxiety
depression
strong craving
fatigue after brief period
Exhaustion results in hypersomnolence (prolonged sleep)
Sleep can be interrupted by brief periods of waking and hyperphagia
Withdrawal and Extinction
Withdrawal is a period of relatively normal function
Extinction is a gradual return to normal function
Withdrawal is a period of relatively normal function
Hours or days of normal mood, sleep, little anxiety
* Little craving for cocaine
* Some report mild cognitive impairment
* Gradual onset of a dysphoric syndrome
dysphoric syndrome (5)
boredom, anergia, anhedonia, anxiety, and increased craving
Extinction is a gradual return to normal function
Normal mood, normal hedonic function
* Intermittent cravings may occur – particularly in response to emotional or environmental
cues
Toxicity Acute overdose results from several main effects
Reduced seizure threshold
Cardiovascular effects
Hyperthermia
Reduced seizure threshold
Due to general increase in neurotransmitter release
Cardiovascular effects
- Increased heart rate and blood pressure can increase risk of stroke, cerebral hemorrhage, tachycardia
and arrhythmia
- Treatment of overdose is administration of
sedative (typically a benzodiazepine) to decrease heart rate and BP, and use of ice or cooling blankets for hyperthermia
Cocaine is the
second most popular illicit drug in the USA second to cannabis
(PCE)
Prenatal cocaine exposure`
- In utero exposure to crack-cocaine was
correlated (in early studies, mostly case studies
or small cohorts) with
- Premature birth
- Lower birth weight
- Mental and physical defects