Pharmacology - antipsychotics

Question 1

Antipsychotic method of action

Answer 1

D2 antagonist - Reduced level of dopamine activity at the D2 receptor

Question 2

Dopamine receptors

Answer 2

Targetted pathways:

• Mesolimbic
• Mesocortical

Unwanted effects:

• Nigrostriatal - movement
• Tuberoinfundibular - HPA (prolactin)

Question 3

Typical antipsychotic side effects

Answer 3

Sedation 
Extrapyramidal side effects 
Weight gain 
QTc prolongation 
Dizziness 
Sexual dysfunction

Question 4

Acute Dystonic Reaction

Answer 4

Abnormal muscle tone resulting in muscular spasm and abnormal posture

• oculogyric crisis
• torticollis

Question 5

Oculogyric crisis

Answer 5

Eyes point involuntarily upwards + hyperextended neck

Question 6

Typical antipsychotics

Answer 6

• Older
• More likely to cause extrapyramidal side effects
• Bind more to muscarinic and histaminic receptors

Question 7

Atypical antipsychotics

Answer 7

• Serotonergic activity

Question 8

Examples of typical antipsychotics

Answer 8

Haloperidol 
Fluoenthixol 
Zuclopenthixol 
Chlorpromazine 
Sulpride

Question 9

Examples of atypical antipsychotics

Answer 9

Clozapine
Olanzapine 
Risperidone 
Quetiapine 
Amisulpride 
Aripiprazole - most tolerable

Question 10

Aripiprazole

Answer 10

D2 partial agonist not an antagonist

Question 11

Extrapyramidal side effects (EPSEs)

Answer 11

Parkinsonism:

• Bradykinesia
• Muscle stiffness
• Tremor
• Tardive dyskinesia
• Akathisia
• Acute dystonia - oculogyric crisis

Question 12

Atypical antipsychotic side effects

Answer 12

Weight gain
Dyslipidaemia
Diabetes

Question 13

Antipsychotic monitoring

Answer 13

Baseline - FBC, Lipids, HbA1c, Weight, ECG, BP and pulse

Weekly - weight (ideally but not in practice)

3 months - FBC, Lipids, HbA1c, Weight, ECG, BP and pulse

Yearly - FBC, Lipids, HbA1c, Weight, ECG, BP and pulse

Question 14

Neuroleptic malignant syndrome

Answer 14

Rare and life-threatening rection to antipsychotics

• fever
• confusion
• muscle rigidity
• sweating
• autonomic instability

Question 15

Cause of death due to neuroleptic malignant syndrome

Answer 15

Rhabdomyolysis
Renal failure
Seizures

Question 16

Risks of neuroleptic malignant syndrome

Answer 16

High potency antipsychotics (typical)
Antipsychotic niave
High dose
Young men

Question 17

Treatment of neuroleptic malignant syndrome

Answer 17

1. Emergency referral to A&E
2. Stop antipyschotics
3. Give benzodiazepines for behavioural disturbance
4. Fluid restriction
5. Reduce temperature - cooling
6. Oxygen - if necessary
7. Rhabdomyolysis - fluids and sodium bicarbonate
8. Relax muscles - dantrolene or lorazepam and 2nd line bromocriptine

Question 18

How to treat an acute dystonic reaction

Answer 18

Procyclidine - anticholinergic

Question 19

Clozapine side effects

Answer 19

• Agranulocytosis/ neutropenia - monitor FBC
• Sedation
• Myocarditis - ECG
• Arrhythmia
• excessive salivation
• weight gain
• constipation
• glucose intolerance

Question 20

Treatment for tardive dyskinesia

Answer 20

Tetrabenazine

Question 21

If clozapine doses are missed for 48+hrs

Answer 21

The dose will need to be restarted again slowly

Question 22

Smoking and clozapine

Answer 22

Smoking speeds up the metabolism of clozapine so smoking cessation can cause clozapine toxicity

Question 23

Torticollis

Answer 23

Unilateral neck pain, spasm and restricted range of movement