Drugs of abuse

Question 1

What are 5 characteristics of the drug dependance syndrome?

Answer 1

• desire or sense of compulsion to take the substance.
• difficulty in controlling use.
• physical withdrawal state.
• progressive neglect of other interests, increasing time obtaining and taking substance.
• persistence with substance regardless of detrimental effect. Be it cognitive, physical or social.

Question 2

Meso-limbic dopamine pathway is involved in what?

Answer 2

Brain reward pathway.

Question 3

Where are the cell bodies of the meso-limbic pathway and where do the neurons terminate?

Answer 3

Cell bodies in VTA, ventral tegmental area and neurons terminate in the nucleus accumbens.

Question 4

Many drugs increase dopamine release where?

Answer 4

Shell of the nucleus accumbens.

Question 5

Give one example of a drug which enhances serotonin and one which is a hallucinogenic NMDA antagonist.

Answer 5

MDMA and ketamine.

Question 6

What are the functions of the dopamine pathways?

Answer 6

Reward (motivation).
Pleasure, euphoria.
Motor function (fine tuning).
Compulsion.
Perserveration.

Question 7

What are the functions of the serotonin pathways?

Answer 7

Mood.
Memory processing.
Sleep.
Cognition.

Question 8

Opiates are agonists where? What effect does this have?

Answer 8

G-protein coupled opioid receptors, reduces neurotransmitter release in brain and periphery.

Question 9

What are the acute effects of opiates?

Answer 9

Euphoria, tranquility, miosis, drowsiness, itching and nausea.

Question 10

What are the chronic effects of opiates?

Answer 10

Anhedonia, depression, constipation, insomnia, dependance.

Question 11

What symptoms are seen when withdrawal precipitates?

Answer 11

Restlessness, muscle and bone pain, insomnia, diarrhoea, cold flashes with goose bumps (cold turkey) and vomiting.

Question 12

When do major withdrawal symptoms peak?

Answer 12

24-72hrs after last dose.

Question 13

Cocaine acts as what by blocking Na+ channels?

Answer 13

Anaesthetic.

Question 14

What are the effects of cocaine?

Answer 14

Euphoria and excitement, increased capacity for work.

Question 15

In high doses what does cocaine cause?

Answer 15

Overactivity of the sympathetic nervous system - tachycardia, hypertension, hyperpyrexia, dilated pupil, palpitations.

Question 16

Is there tolerance with cocaine?

Answer 16

No.

Question 17

What dependance occurs with cocaine and what dependance doesn’t?

Answer 17

Physical dependance does not occur but psychological dependance does.

Question 18

Amphetamines produce what effect?

Answer 18

Increased wakefulness and concentration in association with decreased fatigue and appetite. Performance enhancing.

Question 19

Psychological effects include?

Answer 19

Euphoria, increased libido, energy, self-esteem, self-confidence, aggression, excessive feelings of power.

Question 20

When can amphetamine psychosis occur?

Answer 20

In chronic and high doses.

Question 21

Ecstasy acts as what?

Answer 21

Stimulant and psychedelic.

Question 22

In high doses MDMA can interfere with what?

Answer 22

Temperature regulation.

Question 23

When is MDMA neurotoxic?

Answer 23

Following systemic but not central administration.

Question 24

What does THC mimic?

Answer 24

The effects of small endogenous lipid messengers.

Question 25

Inhibits wide range of neurotransmitter release in the brain and periphery how?

Answer 25

Via G-protein coupled cannabbinoid receptors.

Question 26

What effect do you get in mild and high doses?

Answer 26

Mild can be euphoric, high is dysphoric.

Question 27

What other effects does it have?

Answer 27

Stimulates appetite by stimulating feeding centres in the hypothalamus and possibly the gut. Analgesic.

Question 28

What effects does alcohol have?

Answer 28

CNS depressant, in large doses irritates the stomach, inhibits ADH which leads to dehydration (hangover).

Question 29

What does long term drinking lead to?

Answer 29

Neuropathies eg: Wernicke’s encephalopathy (psychosis). Hepatotoxicities and haematological disorders.

Question 30

What relevance does methadone have in treatment for opiate abuse?

Answer 30

It is a long acting synthetic opiate agonist. Blocks effects of illicit opiate use and decreases opiate craving.

Question 31

Name two other antagonist drugs used to help in abuse

Answer 31

Naltrexone - therapy for opiate addiction.
Mecamylamine - nicotinic acetylcholine receptor antagonist. Blocks rewarding actions of nicotine and cue-induced craving.

Question 32

What is the anti-craving medicine used for alcohol abuse?

Answer 32

Acamprosate - reduces neuronal excitability that occurs during alcohol withdrawal. Naltrexone is also used in alcohol withdrawal. It interferes with positive reinforcement and possibly alcohol-conditioned cues.