BASIC - SUBSTANCE MISUSE Flashcards
Drugs used in NRT?
Nicotine, Varenicline, Bupropion
Reasons for using drugs in NRT?
- Control physical symptoms of nicotine withdrawal alongside non-pharmacological measures
Mechanism of nicotine?
- Nicotine activates CNS nicotinic acetylcholine receptors – causing euphoria and relaxation
Withdrawal symptoms in nicotine withdrawal?
- Nicotine withdrawal causes intense craving, anxiety, depression, irritability and weight gain
Mechanism of NRT?
- NRT – maintains receptor activation
Mechanism of varenicline?
- Varenicline – partial agonist of nicotinic receptors, reduces withdrawal and rewarding effects of smoking
Mechanism of bupropion?
- Bupropion – increases concentrations of NA and dopamine in synaptic cleft, inhibiting reuptake
SE of NRT?
local irritation, GI upset, abnormal dreams
SE of varenicline?
nausea, headache, insomnia, abnormal dreams, suicidal ideation
SE of bupropion?
dry mouth, GI upset, headache, dizziness, impaired concentration, insomnia, depression
Interactions of bupropion?
- Metabolised by CYP450 enzymes
- Increased risk of adverse effects with MAOIs and TCAs
Cautions in varenicline and bupropion?
- Risk of seizures
- Prior head injury
- Drugs that lower seizure threshold
- Psychiatric disease
- Hepatic and Renal impairment
Prescription of NRT?
- 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
Prescription of varenicline & bupropion?
- Treatment with varenicline and bupropion should start 1-2 weeks before stopping – continued for 9-12 weeks
How often do you review NRT therapy?
- Review monthly
Name of vitamin B1?
Thiamine
Indications of thiamine?
- Treatment and prevention of Wernicke’s encephalopathy and Korsakoff’s psychosis (manifestations of severe thiamine deficiency)
Mechanism of thiamine?
- Increases thiamine levels in body
Side effects of thiamine?
- High-dose thiamine rarely causes anaphylaxis
Prescription of thiamine?
- 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
Names of benzodiazepines?
Diazepam, Temazepam, Lorazepam, Chlordiazepoxide, Midazolam
Indications of benzodiazepines?
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
Palliative care indications of benzodiazepines?
- Agitation
- Nausea due to anxiousness or agitation
- Terminal restlessness
- Major haemorrhage
- Anticipatory medicines
Mechanism of benzodiazepines?
- 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
side effects of benzodiazepines?
- 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
Withdrawal symptoms of benzodiazepines?
o Anxiety, insomnia, tremor, agitation, nausea, sweating, seizures, delirium
Cautions of benzodiazepines?
o Elderly more susceptible to effects (lower dose)
o Avoid in respiratory impairment, neuromuscular disease (myasthenia gravis), liver failure (lorazepam if needed)
Prescription of benzodiazepines?
- 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
Management of benzo dependence?
- Methadone given and supervised for at least 3 months
