Drug Dependance Flashcards
Psychomimetic Drug
A drug which mimics the actions of psychosis, including delusions and/or delirium as opposed to just hallucinations.
Amphetamine
Psychomimetic Drug
Action is at DA/NA/5HT receptors
Inhibit DA, NA & 5HT reuptake leading to activation of locus coeruleus and nucleus accumbens.
Mood elevation, anorexia, hyperarousal, hallucinations and delusions - followed by a sense of dysphoria when stores begin to deplete
Use increased number of DA transporters thus after the drug is withdrawn more uptake 1 of DA is seen which leads to reduction in tyrosine hydroxylase activity (catalyses hydroxylation of tyrosine to L-Dopa) - thus less dopamine production.
Clinically used to treat ADHD (stimulent drugs)
Lysergic acid diethylamide (LSD)
Action is predominantly as a 5HT2a agonist - small amount to DA receptors and other 5HT receptors - acts as an agonist
Has somatic (hyperarousal), perceptual (hallucinations) and psychic effects (mind altering)
Very potent
Causes euphoric/dysphoric effects but with little evidence of physical dependence
MDMA (ecstacy)
Has both amphetamine and LSD-like effects.
Affects 5HT system mainly but also DA and NA systems - prolongs NT actions
Chronic use causes destruction in serotonergic neurons, irreversible destruction (primates)
Reduced SERT (serotonin transporter that brings serotonin back into the neuron from the synaptic cleft)
Increased 5-HT2A receptors
Increased excitability in neocortex
Atropine
Muscarinic Ach antagonist
Block of muscarinic control of cognitive function
Hallucinations: altering perception (esp. visual)
Delirium: disorientation, confusion, amnesia
EEG of awake person associate with slow-wave (sleep like)
Somnolence, restlessness and uncoordination
Cannabis/Drobanilol (synthetic cannabis)
Active ingredient (tetrahydrocannabinol) CB1 & CB2 receptor agonsists
Acute effects: impaired cognition & perception, increased appetite, muscle relaxation, decreased reaction time.
Chronic effects: cognitive and emotional problems that can impair a person’s lifestyle
Bronchitis: due to method of administration which is smoking. Chronic use can increase the risk of schizophrenia (particularly those at young age).
Clinical Use: Nabilone - antiemetic for chemotherapy induced vomiting, muscle relaxant for MS, analgesia, anticonvulsant (epilepsy) - work by boosting dopamine neurons via the inhibition NT transmission from GABAergic neurons.
Nabilone (synthetic cannabis)
Works by boosting dopamine neurons via the inhibition NT transmission from GABAergic neurons.
Antiemetic for chemotherapy induced vomiting, muscle relaxant for MS, analgesia, anticonvulsant (epilepsy) -
Ethanol
Used acutely facilitates GABAergic receptors and inhibits NMDA receptors (reduced excitability)
Used chronically - increased NMDA receptor and reduction in GABA receptors (body’s adaptation) which causes a rise in CNS excitability.
Lasting effects of chronic abuse:
1. Neurodegeneration: dementia (due to thiamine deficiency), cerebellar degeneration, peripheral neuropathy.
2. Foetal alcohol syndrome: occurs when mother drinks in 1st trimester - causes physical and behavioural problems
3. Liver damage: fat accumulation → fatty liver →
hepatitis → irreversible necrosis and fibrosis
4. Increased BP and cancer risk
Nicotine
Nicotinic Ach receptor agonist
It becomes a rewarding system specifically when it binds to the α4β2 nicotinic receptor.
Buproprion
inhibits the reuptake of dopamine, serotonin, and norepinephrine; results in increased availability of DA, NA & 5HT in the synaptic cleft for postsynaptic transmission.
Antidepressant drug - clinically used to aid in nicotine withdrawal by reducing cravings.
Varenicline
Partial agonist selective for α4β2 receptor subtype
Clinically used for nicotine craving & withdrawal to help reduce chance of relapse.
Mecamylamine
Full non-selective non-competitive antagonist - ganglionic blocker prevents stimulation of postsynaptic receptors by acetylcholine.
Clinically used as an antiaddictive drug to help cessation of nicotine smoking.
Buprenorphine
Partial agonist of opioid receptors
Used in conjunction with nalaxone to induce rapid opioid withdrawal symptoms thus reducing the attractive effects of the drugs.
Rapid withdrawal effects: dysphoria, purposive searching for drug, nausea, vomiting, muscle aches/cramps: since opioids are pain relieving, watery eyes, runny nose, sweating: due to loss of body fluids, insomnia.
Nalaxone
competitive antagonist at mc, κ, and σ opiate receptors in the CNS, with the highest affinity for the μ receptor.
Used to induce rapid opioid withdrawal symptoms thus reducing the attractive effects of the drugs.
Rapid withdrawal effects: dysphoria, purposive searching for drug, nausea, vomiting, muscle aches/cramps: since opioids are pain relieving, watery eyes, runny nose, sweating: due to loss of body fluids, insomnia.
