Psychopharmacology

Question 1

What are the indications for prescribing lithium?

Answer 1

Bipolar disorder (mood stabiliser)

Question 2

What are the side effects of lithium?

Answer 2

LITHIUM CON

• Leukocytosis (raised WCC)
• Increased weight
• Tremor (fine; coarse in toxicity)
• Hypothyroidism
• Insipidus (diabetes)
• Urine output increased
• Mums beware (teratogenic)
• Cardiac, e.g. long QT
• Oedema
• Neuro/nephrotoxicity

Question 3

Lithium toxicity may be precipitated by…

Answer 3

• Dehydration

- Renal failure

Question 4

Describe the management of lithium toxicity

Answer 4

• Mild/moderate toxicity = fluid resuscitation

- Severe toxicity = haemodialysis

Question 5

Describe the monitoring of lithium levels

Which other blood tests need to be ordered in lithium monitoring?

Answer 5

• 12 hours post-dose
• Weekly until concentrations are stable, then 3-monthly

Thyroid and renal function should be monitored every 6 months

Question 6

Give some examples of:

1) First generation (typical) antipsychotics
2) Second generation (atypical) antipsychotics

Answer 6

1) First generation:
- Haloperidol
- Chlorpromazine
- Prochlorperazine

2) Second generation:
- Quetiapine
- Olanzapine
- Clozapine
- Risperidone
- Aripiprazole (low side-effect profile)

Question 7

Describe the mechanism of action of antipsychotics

Answer 7

Both block postsynaptic dopamine receptors (D2 receptor antagonist)

Question 8

What are the side effects of first generation (typical) antipsychotics?

Answer 8

Extrapyramidal effects:

• Acute dystonia
• Tardive dyskinesia
• Akathisia
• Neuroleptic malignant syndrome (life threatening side effect characterised by rigidity, confusion, pyrexia)

Other side effects: CHAPS

• Cardiac, e.g. long QT
• Hyperprolactinaemia, e.g. galactorrhoea
• Anticholinergic: dry mouth, urinary retention, constipation
• Postural hypotension
• Sedation

Question 9

Antipsychotics should be prescribed with caution in the elderly because there is an increased risk of…

Answer 9

• VTE

- Stroke

Question 10

Which is the most important interaction to be aware of when prescribing both first and second generation antipsychotics?

Answer 10

Other drugs which prolong the QT interval (e.g. SSRIs)

Question 11

What are the side effects of second generation (atypical) antipsychotics?

Answer 11

Metabolic disturbance:

• Weight gain
• Diabetes mellitus

Other side effects: CHAPS

• Cardiac, e.g. long QT
• Hyperprolactinaemia, e.g. galactorrhoea
• Anticholinergic: dry mouth, urinary retention, constipation
• Postural hypotension
• Sedation

Question 12

Which medication can be given to treat acute dystonic reaction?

Answer 12

Procyclidine

Question 13

What are the side effects which are specific to clozapine (compared to other antipsychotics)?

Answer 13

• Agranulocytosis

- Myocarditis

Question 14

Describe the mechanism of action of SSRIs

Answer 14

Inhibit neuronal uptake of 5-HT (serotonin) from the synaptic cleft

Question 15

What are the side effects of SSRIs?

Answer 15

• Increase in suicidal thoughts/behaviour
• Lower seizure threshold
• Prolong QT interval (arrhythmias)
• Hyponatraemia (particularly in the elderly)

Question 16

Give some examples of SSRIs

Answer 16

• Citalopram
• Fluoxetine
• Sertraline

Question 17

Are there any important interactions to be aware of when prescribing an SSRI?

Answer 17

• Serotonin syndrome (co-prescription with MAOIs/tramadol)
• Prolonged QT (co-prescription with antipsychotics)
• Increased risk of GI bleed (co-prescription with aspirin/NSAID)

Question 18

Which SSRI is the treatment of choice…

1) In young patients (under 18)?
2) Post-MI?
3) In women who are breastfeeding?

Answer 18

1) Fluoxetine
2) Sertraline
3) Sertraline

Question 19

Which SSRI carries the highest risk of QT interval prolongation?

Answer 19

Citalopram

Question 20

Describe the mechanism of action of benzodiazepines

Answer 20

Benzodiazepines enhance the effect of GABA (inhibitory neurotransmitter)