PH2113 - Abuse of drugs in theory & practice

Question 1

What is Drug Abuse?

Answer 1

Administration of any pharmacological substance in a way which deviates from approved medical/social paterns

Question 2

How can self-administration lead to drug abuse?

Answer 2

Excessive self medication
Abuse of drugs in sport
Patient non-compliance

Question 3

How can administration by others lead to drug abuse?

Answer 3

Over, or mis-prescribing
- pharmacist responsible
Unnecessary counter prescribing
- pharmacist responsible
Excessive antibiotic addition to animal foodstuffs in factory farming

Question 4

Give examples of legal drugs that can be abused

Answer 4

Caffeine
Alcohol
Tobacco

Question 5

Give examples of OTC drugs that can be abused

Answer 5

Codeine based medicines
Dextromethorphan based medicines
Sedative antihistamines
Decongestants
- pseudoephedrine
- ephedrine
Laxatives

Question 6

Give examples of prescribed medicines that can be abused

Answer 6

Opioid analgesia
Benzodiazepines

Question 7

What are the three classes of illegal drugs?

Answer 7

Class A, B and C

Question 8

Give examples of Class A drugs

Answer 8

Heroin
Cocaine
Ecstasy
LSD
Morphine

Question 9

Give examples of Class B drugs

Answer 9

Amphetamines
Ketamine
Cannabis
Barbiturates

Question 10

Give examples of Class C drugs

Answer 10

Benzodiazepines
Anabolic steroids
Amphetamine-related drugs
Human Chorionic Gonadotrophin (HCG)

Question 11

What is addiction?

Answer 11

Complex process involving the interaction of biological, psychological and social factors

Question 12

What are the biological factors that contribute to addiction?

Answer 12

Genetic predisposition
Neuroplasticity
- dopamine mediated pathways in the prefrontal cortex and amygdala
Tolerance
- desensitisation
- tachyphylaxis
Withdrawal

Question 13

What are the psychological factors that contribute to addiction?

Answer 13

Impulsivity
Anxiety/other distress
Reward sensitivity

Question 14

What are the social factors that contribute to addiction?

Answer 14

Drug use by friends or family
Childhood neglect and trauma
Poverty
- homelessness
- unemployment
- poor education

Question 15

What is tolerance?

Answer 15

The need to employ increasing doses of drug in order to produce the same effect as on first exposure

Question 16

What are the three types of tolerance?

Answer 16

Metabolic/dispositional tolerance
- metabolic/PK
Physiological/functional tolerance
- PD/non-associative
Behavioural/conditioned tolerance
- behavioural/learned/context-specific

Question 17

What is dependence?

Answer 17

A state/condition where there is compulsion to take a drug continually in order to experience its effects and sometimes to avoid the physical discomfort of its absence

Tolerance may/may not be presence

Question 18

What are the two types of drug dependence?

Answer 18

Psychological
Physical

Question 19

What are the four key characteristics of tolerance?

Answer 19

Reversible
- once exposure to the drug is discontinued
Dependent on the dose and frequency of drug exposure
Variable time course and extent of tolerance development between different drugs
Not all drug effects develop the same amount of tolerance

Question 20

How does metabolic/dispositional tolerance take place?

Answer 20

Adaptations in drug ADME
- less drug at action site
- need to take more

Barbiturates/alcohol
- induce hepatic microsomal enzymes
- enhance metabolism so metabolised faster

Question 21

How does physiological/functional tolerance take place?

Answer 21

Changes in properties and function of target tissue
- less sensitive to the substance

Question 22

Give examples of how physiological/functional tolerance takes place

Answer 22

Changes in receptor number/density
Receptor uncoupling
Exhaustion of mediators
Tolerance at reuptake transporter

Question 23

What are the two mechanisms of functional tolerance?

Answer 23

Changes in receptor number/density
- compensatory changes
- hours/days

Receptor down-regulation
- usually with agonists on prolonged exposure
Receptor up-regulation
- usually with antagonists or low levels of endogenous agonist/transmitter
- denervation