BASIC - SUBSTANCE MISUSE

Question 1

Drugs used in NRT?

Answer 1

Nicotine, Varenicline, Bupropion

Question 2

Reasons for using drugs in NRT?

Answer 2

• Control physical symptoms of nicotine withdrawal alongside non-pharmacological measures

Question 3

Mechanism of nicotine?

Answer 3

• Nicotine activates CNS nicotinic acetylcholine receptors – causing euphoria and relaxation

Question 4

Withdrawal symptoms in nicotine withdrawal?

Answer 4

• Nicotine withdrawal causes intense craving, anxiety, depression, irritability and weight gain

Question 5

Mechanism of NRT?

Answer 5

• NRT – maintains receptor activation

Question 6

Mechanism of varenicline?

Answer 6

• Varenicline – partial agonist of nicotinic receptors, reduces withdrawal and rewarding effects of smoking

Question 7

Mechanism of bupropion?

Answer 7

• Bupropion – increases concentrations of NA and dopamine in synaptic cleft, inhibiting reuptake

Question 8

SE of NRT?

Answer 8

local irritation, GI upset, abnormal dreams

Question 9

SE of varenicline?

Answer 9

nausea, headache, insomnia, abnormal dreams, suicidal ideation

Question 10

SE of bupropion?

Answer 10

dry mouth, GI upset, headache, dizziness, impaired concentration, insomnia, depression

Question 11

Interactions of bupropion?

Answer 11

• Metabolised by CYP450 enzymes

- Increased risk of adverse effects with MAOIs and TCAs

Question 12

Cautions in varenicline and bupropion?

Answer 12

• Risk of seizures
• Prior head injury
• Drugs that lower seizure threshold
• Psychiatric disease
• Hepatic and Renal impairment

Question 13

Prescription of NRT?

Answer 13

• Continuous-release patch or immediate-release tablet/gum/spray
• Applied in morning to dry, hairless area of skin and taken off at night
• Treatment started a few weeks before cessation attempt (at least 2 weeks) and last 3 months before reducing dose

Question 14

Prescription of varenicline & bupropion?

Answer 14

• Treatment with varenicline and bupropion should start 1-2 weeks before stopping – continued for 9-12 weeks

Question 15

How often do you review NRT therapy?

Answer 15

• Review monthly

Question 16

Name of vitamin B1?

Answer 16

Thiamine

Question 17

Indications of thiamine?

Answer 17

• Treatment and prevention of Wernicke’s encephalopathy and Korsakoff’s psychosis (manifestations of severe thiamine deficiency)

Question 18

Mechanism of thiamine?

Answer 18

• Increases thiamine levels in body

Question 19

Side effects of thiamine?

Answer 19

• High-dose thiamine rarely causes anaphylaxis

Question 20

Prescription of thiamine?

Answer 20

• Patients at high risk of thiamine deficiency given Pabrinex (compound preparation of B and C vitamins)
  o Prophylaxis dose – 1 pair 12-hourly for 3 days
  o Treatment dose are higher
• Oral thiamine 25-300mg daily started subsequently

Question 21

Names of benzodiazepines?

Answer 21

Diazepam, Temazepam, Lorazepam, Chlordiazepoxide, Midazolam

Question 22

Indications of benzodiazepines?

Answer 22

1st line – Seizures, status epilepticus
- Long-acting lorazepam/diazepam
1st line – alcohol withdrawal
- Oral long-acting chlordiazepoxide
Sedation for interventional procedures
- Short-acting midazolam
Short-term treatment of severe anxiety, insomnia
- Intermediate-acting temazepam given at bedtime
Adjunct in opioid dependence
- By mouth using oral solution
- Initially 10-30mg daily, increased in steps of 5-10mg daily until no signs of dependence

Question 23

Palliative care indications of benzodiazepines?

Answer 23

• Agitation
• Nausea due to anxiousness or agitation
• Terminal restlessness
• Major haemorrhage
• Anticipatory medicines

Question 24

Mechanism of benzodiazepines?

Answer 24

• γ-aminobutyric acid type A (GABAA) receptor is a chloride channel
• Opens in response to GABA, making the cell more resistant to depolarisation, the main inhibitory neurotransmitter in the brain
• Benzodiazepines facilitate and enhance binding of GABA to the GABAA receptor
• Depressant effect on synaptic transmission

Question 25

side effects of benzodiazepines?

Answer 25

- Dose-dependent drowsiness, sedation and coma o Relatively little cardiorespiratory depression in benzodiazepine overdose - Loss of airway reflexes can lead to airway obstruction and death - If used regularly, tolerance and dependence develop

Question 26

Withdrawal symptoms of benzodiazepines?

Answer 26

o Anxiety, insomnia, tremor, agitation, nausea, sweating, seizures, delirium

Question 27

Cautions of benzodiazepines?

Answer 27

o Elderly more susceptible to effects (lower dose) | o Avoid in respiratory impairment, neuromuscular disease (myasthenia gravis), liver failure (lorazepam if needed)

Question 28

Prescription of benzodiazepines?

Answer 28

- Therapy only short-term for anxiety or insomnia o Risk of dependence (<4 weeks) - Do not drive or operate heavy machinery after taking drug - Sedation may persist for a few days

Question 29

Management of benzo dependence?

Answer 29

- Methadone given and supervised for at least 3 months