S13) Psychopharmacology

Question 1

What causes depression?

Answer 1

• Theory – low serotonin production in brain
• Additional – environmental triggers e.g. death, divorce, trauma
• Genetic susceptibility

Question 2

How does depression present?

Answer 2

• Mental – low mood, anhedonia, fatigue, sleep disturbance, suicidal thoughts
• Physical – pain, irritable bowel, loss of appetite, low libido, weight loss/gain

Question 3

How does one diagnose / determine the severity of depression?

Answer 3

Beck’s depression scale:

• Mild / moderate / severe?
• Are activities of daily living affected?

Question 4

How does one manage a patient presenting with depression?

Answer 4

• Assess suicide risk?
• Mental health act assessment/sectioning
• Psychological therapy (first line) e.g. counselling/cognitive behavioural therapy = first line
• Antidepressants (first line) e.g. SSRI’s

Question 5

What are the indications for antidepressants?

Answer 5

• Depression
• Anxiety
• Neuropathic pain

Question 6

Provide some examples of antidepressants

Answer 6

• Serotonin selective reuptake inhibitor (first line)
• Tricyclic antidepressants
• Serotonin/noradrenergic reuptake inhibitor
• Monoamine oxidase inhibitor

Question 7

What are the principles of prescribing for antidepressants?

Answer 7

• Try one antidepressant for at least 6 weeks before switching to another
• Even if feeling better, continue for at least a year to reduce relapse risk

Question 8

Provide two examples of SSRIs

Answer 8

• Citalopram
• Fluoxetine

Question 9

In three steps, describe the mechanism of action of SSRIs

Answer 9

⇒ Limits reabsorption of serotonin into the presynaptic cell (neurone)

⇒ Increases level of serotonin in the synaptic cleft available to bind to the postsynaptic receptor

⇒ Carries on action potential

Question 10

What are the common side effects of SSRIs?

Answer 10

• Nausea
• Sexual dysfunction
• Insomnia

Question 11

What is serotonin syndrome?

Answer 11

Serotonin Syndrome is a life threatening presentation which occurs within a few weeks of initiating SSRIs or when 2 used at once

Question 12

What is the presentation of serotonin syndrome?

Answer 12

• Tachycardia
• Sweating
• Dilated pupils
• Myoclonus
• Hyperreflexia
• Hyperthermia

Question 13

What are the complications of serotonin syndrome?

Answer 13

• Seizures
• Muscle breakdown
• Complications of hyperthermia

Question 14

Provide an example of a TCA

Answer 14

Amitriptyline

Question 15

What are the indications of TCAs?

Answer 15

• Depression
• Neuropathic pain

Question 16

What is the mechanism of action of TCAs?

Answer 16

Mechanism of action – act largely as SNRIs (serotonin noradrenaline reuptake inhibitors)

Question 17

What are the common side effects of TCAs?

Answer 17

Due to anti muscarinic action:

• Dry mouth/nose
• Blurry vision
• Constipation
• Urinary retention
• Cognitive and/or memory impairment

Question 18

What are the cardiotoxic and neurotoxic adverse drug reactions of TCAs?

Answer 18

• Cardiotoxic: can result in life threatening inhibitors
• Neurotoxic: seizures, hallucinations, delirium and coma

Question 19

What are the two types of antipsychotics?

Answer 19

• Typical (old generations - 1950s)
• Atypical (new generation)

Question 20

Describe the mechanism of action of typical antipsychotics

Answer 20

• Typical antipsychotics act predominantly as dopamine antagonists
• More likely to cause extrapyramidal side effects

Question 21

Provide two examples of typical antipsychotics

Answer 21

• Haloperidol
• Chlorpromazine

Question 22

Describe the mechanism of action of atypical antipsychotics

Answer 22

• Atypical antipsychotics act at serotonin (5HT2) receptors as agonists as well as dopamine antagonists
• More effective in reducing negative symptoms of schizophrenia

Question 23

Provide four examples of atypical antipsychotics

Answer 23

• Risperidone
• Quetiapine
• Aripiprazole
• Clozapine
• Olanzapine

Question 24

Identify and describe the four main side effects arising from treatment with antipsychotics

Answer 24

• Anticholinergic – dry mouth, urinary retention, blurred
• Serotonergic – nausea, sexual dysfunction, insomnia (also due to anti-adrenergic)
• Metabolic syndrome – increased blood glucose, obesity, increased cardiovascular risk
• Antidopaminergic – extrapyramidal side effects

Question 25

What is a specific side effects of clozapine?

Answer 25

Clozapine can cause agranulocytosis resulting in neutropenia (requires FBC monitoring)

Question 26

What are extrapyramidal side effects?

Answer 26

• Extrapyramidal side effects are side effects caused by all dopamine antagonists
• They are more prominent in the typical antipsychotics as these largely act on D2 receptors

Question 27

Identify and describe four extrapyramidal side effects

Answer 27

• Dystonia – sustained muscle contraction resulting in abnormal fixed posture
• Akathisia – internal feeling of restlessness
• Tardive dyskinesia – abnormal, involuntary, repetitive movements e.g. grimacing, sticking out the tongue or smacking of the lips
• Pseudo-parkinsonism – rigidity, tremor and increased tone

Question 28

What is neuroleptic malignant syndrome?

Answer 28

Neuroleptic malignant syndrome is life threatening reaction within 2 weeks of initiating antipsychotics characterised by fever, altered mental status, muscle rigidity and autonomic dysfunction (tachycardia, labile BP, flushing)

Question 29

Provide three examples of anxiolytics (benzodiazepines)

Answer 29

• Lorazepam
• Diazepam
• Midazolam

Question 30

What are the indications for anxiolytics?

Answer 30

• Anxiety (short term – orally)
• Anticonvulsant in acute seizure (IM, IV, buccal)
• Sedative

Question 31

In two steps, describe the mechanism of action of anxiolytics

Answer 31

⇒ Potentiate the action of GABA (main inhibitory neurone)

⇒ Increase opening of chloride channels – hyperpolarized membrane