Lecture 15: Drugs of abuse Flashcards
What is tolerance?
The reduction in response to a drug after a repeated administrisation. May be innate or aquired. Very common.
Where does addiction, drug abuse and drug dependence manifest?
In the mesolimbic dopamine system
- The nucleus accumbens (pleasure centre) linked to the ventral tegmental area by this system.
Physical dependence is?
A state that develops as a result of tolerance produced by resetting of homeostatic mechanisms in response to repeated drug abuse.
Characterised by a withdrawal syndrome
Withdrawal syndromes are?
Evidence of physical dependence
Caused by removal of the drug or CNS hyperarousal
opposite to drug effect
Opoid withdrawal syndrome symptoms?
Symptoms:
Craving, restlessness, irritability, Inc. sensitivity to pain, nausea, muscle aches, dysphoria
autonomic dysfunction: sweating, tachycardia, hypertension, vomiting, diarrhoea, fever
3 Origins of drug abuse?
- The Drug itself
- Reinforcement is the property that makes you want it again
- what is does to you and how fast it does this
- Convenience of administration - The user
- Their personality (genetic, development, upbringing)
- Pharmacokinetic, pharmacodynamic
- other psychiatric conditions - The environment
- Employment, peer pressure, education levels
Drug of abuse classifications?
Stimulants
Mixed
Depressants
Alcohol as a drug of abuse?
Delerium Tremens symptoms?
- Is a CNS depressant that also impairs recent memory
- Increased does leads to sedation, coma then death
- As tolerance develops sedation is reduced but lethal dose remains unchanged
DT: severe agitation, confusion, visual hallucinations, fever, profuse sweating, nausea, dilated pupils
- Happens in about 5% of people who suddenly stop but 50% will get withdrawal that is not as bad.
Chronic alcohol abuse?
Liver cirrhosis - fulminant hepatic failure GI bleed
Cardiac failure - dilated cardiomyopathy, heart failure
Cushing’s, malnutrition, GI cancers, pancreatitis, FAS
Opoid benefits and AE?
Analgesia
Sedation
Cough supression
Respiratory depression (kills you)
Constipation, nausea, vomiting
Hypotension, Bradycardia
Heroin - diamorphine
Euphoric rush + period of sedation and tranquility
widely used in the UK for analgesia
Order of Opioids?
diamorphine >> fentanyl > Pethidine > Morphine > codeine
- Chronic pain + opioids = potential for abuse
Methamphetamine (speed)?
Increases release and reduces the re-uptake of CNS catecholamines - dopamine, noradrenaline and seratonin
Ritalin acts differently but does essentially the same thing.
inc = libido, energy, self-esteem, agression, hallucinations, BP, arythmias, renal failure, death
Physical dependence is less than other drugs but psychological dependence is significant.
Cocain beginnings and use?
Dervied from coca leaves
local anaesthetic and vasoconstrictors
potent inhibitor of catecholamines re-uptake
Mixed with baking soda + water = crack cocaine and has a pKa closer to that of the body so absorbed much faster.
Lipid soluble = potent psychostimulant
AE of cocaine?
Seizure and Cardiotoxicity causing death
Highly addictive and shows some tolerance but with a constant lethal dose much like alcohol.