Addiction

Question 1

Define what is tolerance to a drug

Answer 1

Reduced responsiveness to a drug caused by previous administration

Question 2

What drugs can you develop a tolerance to?

Answer 2

Opioids
Ethanol
Barbiturates
BZP’s

Question 3

What are the mechanisms of dispositional tolerance?

Answer 3

• Less drug reaches the active site
• Less absorbed
• Faster metabolism
• More excreted

Question 4

Does tolerance = dependence?

Answer 4

Development of tolerance may also lead to withdrawal symptoms

Normal ST = normal response
Drug effect = reduced response
Drug tolerance = normal response
Drug withdrawal = increased response

Question 5

What is the withdrawal phenomena?

Answer 5

Withdrawal effect is usually the reverse of the acute effect

Question 6

What are the reward centres?

Answer 6

Reward pathway = neurons from ventral tegmental area (VTA) to nucleus acumbens and prefrontal cortex

• When VTA are simulated, dopamine is released
• This causes a sensation of pleasure and reward

Question 7

What is the interaction between drugs and the reward centres?

Answer 7

Some drugs tap into this reward pathway and increase dopamine levels
-Heroin, amphetamine, cocaine and alcohol

This produces the psychological component of addiction = craving

Question 8

What are examples of stimulants?

Answer 8

Cocaine

Amphetamine

Question 9

What is cocaine?

Answer 9

Most potent natural stimulant
Extracted from leaves of coca plant
-Chewed or brewed
-Hydrochloride is snorted or injected
-Crack is smoked
Formally used in ENT surgery

Question 10

What are the effects of cocaine?

Answer 10

Depends on dose and rate of entry to brain
-Smoking = immediate
-Injecting = 10-15sec
-Snorting = 3-5mins
Crack intense but over in 15mins

Stimulant and euphorant, alertness an energy
Increased confidence and impaired judgement
Lessens appetite and desire for sleep

Damage to airways, convulsions and resp failure, arrhythmia’s and MI, hypertension, toxic confusion and psychosis

Question 11

What are the cocaine withdrawal effects?

Answer 11

Depression
Irritability
Agitation
Craving
Hyperphagia
Hypersomnia

Question 12

What is amphetamine?

Answer 12

Sniffed, swallowed or injected
Effects are similar to cocaine but lasts longer
Toxic confusion occasionally with convulsions and death
Amphetamine psychosis in heavy chronic use

Question 13

What are opiates?

Answer 13

Opium
Morphine
Heroine
Methadone
Codeine and dihydrocodeine

Question 14

What is heroin?

Answer 14

Diamorphine
In a powder or as a tar like substance
|snorting, smoking and injection
Smoking is the safest and IV is the most dangerous

Question 15

What are the effects of heroin?

Answer 15

Analgesia
Drowsiness and reduced consciousness/coma
Mood changes
Resp depression
Cough depression
Bradycardia and hypotension
Lowers body temp
Pupil constriction
Constipation

Question 16

What are the effects of opiates?

Answer 16

Intense but transient feeling of pleasure

• Rush
• Almost orgasmic
• Physical and emotional anaesthetic

Side effects

• Nausea and vomiting + headache
• Phlebitis, anorexia and constipation
• Tolerance, withdrawal and social + health problems

Question 17

What is the opiate withdrawal syndrome?

Answer 17

Craving
Insomnia
Yawning
Muscle pain
Increased secretions
Dilated pupils
Piloerection

Question 18

What happens in methadone maintenance?

Answer 18

Decriminalises drug use
Allows normalisation of lifestyle
Reduce IV misuse
Leakage onto the illicit market

Question 19

What is Ecstasy (MDMA)?

Answer 19

Relaxed euphoric state without hallucinations
Euphoria followed by feeling of calm
Increased sociability
Inability to distinguish between what is and what isnt desirable
Effects after 20 mins to 2-4 hours

Question 20

What are the side effects of Ecstasy (MDMA)?

Answer 20

Nausea and dry mouth
Increased BP and temp
Large dose = anxiety and panic
Drug induced psychosis
Liver and brain cell damage ?

Question 21

What is cannabis?

Answer 21

Relaxing or stimulating
Euphoriant
Increased sociability and hilarity
Increases appetite
Changes in time perception
Synaesthesia

High dose = anxiety, panic, persecutory ideation, hallucinatory activity

Resp problems, toxic confusion, exacerbation of mental illness and psychosis?

Question 22

What are anabolic (Androgenic) steriods?

Answer 22

Testosterone and synthetic analogues
Prescribed in hypogonadism, muscle dystrophy and anaemias

Muscle hypertrophy in the upper body
Skin = acne and stretch marks
Feminisation in males and gynaecomastia
Virilisation in women = hirtuism, deep voice, clitoral enlargement, hair thinning and menstrual irregularities

CV = increased cholesterol and hypertension
Growth deficits
Liver disease = jaundice and tumours

Question 23

What are the psychological side effects of steriods?

Answer 23

Irritability and anger
Hypomania and mania
Depression and suicidality on withdrawal

Question 24

What are the mechanisms of pharmacodynamic tolerance?

Answer 24

• Drug has less action on the active site
• Fewer drug receptors
• Less efficient drug receptors = down regulation or reduced down stream signalling
• Some other compensatory mechanism