antipsychotics_flashcards

Question 1

What are the two main categories of antipsychotics?

Answer 1

Typical and atypical antipsychotics

Question 2

What is the mechanism of action of typical antipsychotics?

Answer 2

Dopamine D2 receptor antagonists, blocking dopaminergic transmission in the mesolimbic pathways

Question 3

What is the mechanism of action of atypical antipsychotics?

Answer 3

Act on a variety of receptors (D2, D3, D4, 5-HT)

Question 4

What are common adverse effects of typical antipsychotics?

Answer 4

Extrapyramidal side-effects and hyperprolactinaemia

Question 5

What are common adverse effects of atypical antipsychotics?

Answer 5

Extrapyramidal side-effects and hyperprolactinaemia less common, metabolic effects

Question 6

Give examples of typical antipsychotics

Answer 6

Haloperidol, Chlorpromazine

Question 7

Give examples of atypical antipsychotics

Answer 7

Clozapine, Risperidone, Olanzapine

Question 8

List extrapyramidal side-effects (EPSEs) associated with typical antipsychotics

Answer 8

Parkinsonism, acute dystonia, akathisia, tardive dyskinesia

Question 9

What is acute dystonia and how may it be managed?

Answer 9

Sustained muscle contraction (e.g. torticollis, oculogyric crisis), managed with procyclidine

Question 10

What is akathisia?

Answer 10

Severe restlessness

Question 11

What is tardive dyskinesia?

Answer 11

Late onset of choreoathetoid movements, abnormal, involuntary, may be irreversible

Question 12

What warnings has the Medicines and Healthcare products Regulatory Agency issued for antipsychotics in elderly patients?

Answer 12

Increased risk of stroke, increased risk of venous thromboembolism

Question 13

List other side-effects of antipsychotics

Answer 13

Antimuscarinic effects, sedation, weight gain, raised prolactin, impaired glucose tolerance, neuroleptic malignant syndrome, reduced seizure threshold, prolonged QT interval

Question 14

What are the antimuscarinic side-effects of antipsychotics?

Answer 14

Dry mouth, blurred vision, urinary retention, constipation

Question 15

What is neuroleptic malignant syndrome?

Answer 15

Pyrexia, muscle stiffness

Question 16

What side effect is associated with raised prolactin due to antipsychotic use?

Answer 16

Galactorrhoea due to inhibition of the dopaminergic tuberoinfundibular pathway

Question 17

Which antipsychotic is particularly associated with prolonged QT interval?

Answer 17

Haloperidol

Question 18

summarise anti-psychotics

Answer 18

Antipsychotics

Antipsychotics are a group of drugs used in the management of schizophrenia and other forms of psychosis, mania and agitation. They are usually divided into typical and atypical antipsychotics. The atypical antipsychotics were developed due to the problematic extrapyramidal side-effects which are associated with the first generation of typical antipsychotics.

Typical antipsychotics Atypical antipsychotics
Mechanism of action Dopamine D2 receptor antagonists, blocking dopaminergic transmission in the mesolimbic pathways Act on a variety of receptors (D2, D3, D4, 5-HT)
Adverse effects Extrapyramidal side-effects and hyperprolactinaemia common Extrapyramidal side-effects and hyperprolactinaemia less common
Metabolic effects
Examples Haloperidol
Chlorpromazine Clozapine
Risperidone
Olanzapine

The rest of this section will focus on typical antipsychotics, with atypical antipsychotics covered elsewhere.

Extrapyramidal side-effects (EPSEs)
Parkinsonism
acute dystonia
sustained muscle contraction (e.g. torticollis, oculogyric crisis)
may be managed with procyclidine
akathisia (severe restlessness)
tardive dyskinesia (late onset of choreoathetoid movements, abnormal, involuntary, may occur in 40% of patients, may be irreversible, most common is chewing and pouting of jaw)

The Medicines and Healthcare products Regulatory Agency has issued specific warnings when antipsychotics are used in elderly patients:
increased risk of stroke
increased risk of venous thromboembolism

Other side-effects
antimuscarinic: dry mouth, blurred vision, urinary retention, constipation
sedation, weight gain
raised prolactin
may result in galactorrhoea
due to inhibition of the dopaminergic tuberoinfundibular pathway
impaired glucose tolerance
neuroleptic malignant syndrome: pyrexia, muscle stiffness
reduced seizure threshold (greater with atypicals)
prolonged QT interval (particularly haloperidol)

Question 19

A 60-year-old female with paranoid schizophrenia reports a two week history of fatigue, thirst, and frequent urination.

You review her prescribed medications and note that she is on long-term olanzapine, ramipril, and procyclidine.

Which of the following investigations would be most helpful in diagnosing her condition?

Full blood count (FBC)
Urea and electrolytes (U&Es)
Lipid screen
Thyroid function tests (TFTs)
Fasting glucose levels

Answer 19

Fasting glucose levels

Long-term atypical antipsychotics can lead to the development of glucose dysregulation and diabetes

The symptoms that this patient reports are most consistent with a diagnosis of type II diabetes mellitus (T2DM).

Long-term atypical antipsychotics are frequently associated with the development of metabolic syndrome, including glucose dysregulation and diabetes. The measurement of fasting glucose or HbA1c levels forms an integral part of long-term antipsychotic monitoring.

A FBC may reveal anaemia but would not account for the polyuria and polydipsia in this scenario. Similarly low thyroid levels may explain fatigue but would not account for the other symptoms.

A lipid screen would be helpful to track the development of metabolic syndrome but would not help with establishing a diagnosis of diabetes.

Finally, U&Es would be helpful to assess renal function and may reveal a reduced estimated glomerular filtration rate (eGFR) as a consequence of T2DM, but this alone would not be diagnostic.