Lecture 15: Drugs of abuse

Question 1

What is tolerance?

Answer 1

The reduction in response to a drug after a repeated administrisation. May be innate or aquired. Very common.

Question 2

Where does addiction, drug abuse and drug dependence manifest?

Answer 2

In the mesolimbic dopamine system

• The nucleus accumbens (pleasure centre) linked to the ventral tegmental area by this system.

Question 3

Physical dependence is?

Answer 3

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

Question 4

Withdrawal syndromes are?

Answer 4

Evidence of physical dependence

Caused by removal of the drug or CNS hyperarousal

opposite to drug effect

Question 5

Opoid withdrawal syndrome symptoms?

Answer 5

Symptoms:

Craving, restlessness, irritability, Inc. sensitivity to pain, nausea, muscle aches, dysphoria

autonomic dysfunction: sweating, tachycardia, hypertension, vomiting, diarrhoea, fever

Question 6

3 Origins of drug abuse?

Answer 6

1. 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
2. The user
   - Their personality (genetic, development, upbringing)
   - Pharmacokinetic, pharmacodynamic
   - other psychiatric conditions
3. The environment
   - Employment, peer pressure, education levels

Question 7

Drug of abuse classifications?

Answer 7

Stimulants

Mixed

Depressants

Question 8

Alcohol as a drug of abuse?

Delerium Tremens symptoms?

Answer 8

• 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.

Question 9

Chronic alcohol abuse?

Answer 9

Liver cirrhosis - fulminant hepatic failure GI bleed

Cardiac failure - dilated cardiomyopathy, heart failure

Cushing’s, malnutrition, GI cancers, pancreatitis, FAS

Question 10

Opoid benefits and AE?

Answer 10

Analgesia

Sedation

Cough supression

Respiratory depression (kills you)

Constipation, nausea, vomiting

Hypotension, Bradycardia

Question 11

Heroin - diamorphine

Answer 11

Euphoric rush + period of sedation and tranquility

widely used in the UK for analgesia

Question 12

Order of Opioids?

Answer 12

diamorphine >> fentanyl > Pethidine > Morphine > codeine

• Chronic pain + opioids = potential for abuse

Question 13

Methamphetamine (speed)?

Answer 13

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.

Question 14

Cocain beginnings and use?

Answer 14

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

Question 15

AE of cocaine?

Answer 15

Seizure and Cardiotoxicity causing death

Highly addictive and shows some tolerance but with a constant lethal dose much like alcohol.

Question 16

Removal of drugs from the blood in overdose cases?

Answer 16

Intralipid = fat emulsion that binds to many drugs over albumin

Question 17

Synthetic Cannabinoids?

Answer 17

Addictive with bad withdrawal

Psychosis, Seizures, Renal Failure, Heart Failure, Arrythmia

Much more potent than Marijuana

Question 18

Propofol?

Answer 18

Most widely used anaesthetic induction agent

Safe, reliable, effective, rapid onset/offest, minimal SE

Narrow therapeutic index