Drugs of Dependence Flashcards
What are commonly abused opioids?
morphine, heroin - cause eupohira
What are commonly abused CNS depressants?
alcohol, diazepam (valium) - reduce anxiety
What are commonly abused CNS stimulants?
cocaine, amphetamines, MDMA - increase energy
What are commonly abused cannabinoids and hallucinogens?
delta-9-THC and LSD - alter perception
What general areas of the brain are associated with drug abuse and addiction?
reward and salience, memory and learning, motivation and drive, inhibitory control
What areas of the brain are associated with reward and salience?
nucleus acumbens and ventral pallidum
What areas of the brain are associated with memory and learning?
Hippocampus and amygdala
What areas of the brain are associated with motivation and drive?
orbitofrontal cortex, subcallosal cortex
What areas of the brain are associated with inhibitory control?
prefrontal cortex, anterior cingulate gyrus
How do drugs of dependence generally affect the brain?
increase dopamine levels in the nucleus acumbens (reward/salience area)
What are key modulating transmitters of dopaminergic transmission?
acetylcholine, serotonin, noreadrenaline, GABA, glutamate, opiods
CNS effects of amphetamine
releases noreadrenaline in the periphery; much more efficient at releasing dopamine and serotonin in CNS
General effects of amphetamines (and cocaine)
vary with mood, dose, personality, environment: mood elevation, euphoria, increased locomotor activity, reinforcement of stereotypic behaviours; fatigue postponed, confidence, speedy performance, decreased accuracy
Overdose effects of amphetamines (and cocaine)
anxiety, nervous and physical tension, tremors, confusion, dizziness, time passes quickly, hyperthermia, tachycardia, hypertension, vascular collapse and death, psychosis and hallucinations
Dependence of amphetamines is related to
dopaminergic actions in nuclear accumbens; baseline (depression, lonely); withdrawal symptoms (lethargy, sleep, increased appetite, depression)
CNS effects of MDMA (methylenedioxymetamphetamine/ecstasy)
release of dopamine and serotonin
General effects of MDMA
stimulant and hallucinogenic, feelings of closeness, empathy, love, and heightened self-awareness; increased HR and BP, disrupted thermoregulation; potential degeneration of 5-HT and DA neurons by ROS metabolites
General effects of LSD
visual, auditory, and tactile hallucinations (sensory modalities confused); disruption of thought process; dependence and tolerance (applies to other psychotomimetics as well ie need more of other drugs for an effect too); 5-HT2 receptor agonist activating autoreceptors on neurones in Raphe
General effects of caffeine
increase alertness, well being, delays onset of sleep, stimulates mental activity (postpones boredom, fatigue, inattentiveness), enhanced intellectual and motor performance
General effects of delta-9-THC
sharpened sensory awareness, increased intensity of sounds and lights, relaxation and well being,
General effects of ethanol
increased confidence, euphoria; at higher doses aggression and mood swings; loss of motor coordination, slurred speech; liver damage, neurodegeneration, foetal impairment
CNS effects of ethanol
inhibit Ca2+ channel opening (inhibits neurotransmission), enhance GABA-A action, inhibit glutamate receptors (NMDA channels), tolerance and dependence
Pharmacokinetic dependence involves
how quickly the drug is metabolised
Pharmacodynamic dependence involves
how the receptors interact at a mechanistic level
What are the effects of tricyclic antidepressants?
inhibit neuronal uptake of noradrenaline and serotonin; antagonise a-aRs, muscarinic receptors, histamine receptors, and serotonin receptors
What are the negatives of tricyclic antidepressants?
poor selectivity; takes weeks to develop effects; side effects; narrow therapeutic window
Effects of monoamine oxidase inhibitors
increase levels of serotonin and noreadrenaline (moreso than dopamine)
Side effects of monoamine oxidase inhibitors
reversible: postural hypotension, dizziness, nausea, insomnia; irreversible - ‘cheese reaction’ foods containing tyramine (cheese, red wine, chocolate, bananas) precipitate hypertensive crisis
Side effects of SSRIs
nausea, insomnia, agitation, weight change, loss of libido; in conjunction with MAOI and TCA caused serotonin syndrome: hyperthermia, muscle rigidity, and cardiovascular collapse
Where is the focus of new antidepressant drugs?
anti-depressant activity (MAOI, TCs), anxiolytic activity (SSRI, SSNRI) and pro-cognitive activity to elevate mood (new drugs)
