Chapter 34: Antipsychotic Agents and Their Use in Schizophrenia

Question 1

Compare and contrast chlorpromazine and haloperidol in mechanism, onset, uses, and side effects.

Answer 1

• Both block D2 receptors; chlorpromazine also blocks ACh, histamine, and NE more strongly.
• Onset is similar (1–2 days initial, weeks to months full).

Chlorpromazine is low-potency with high sedation, orthostatic hypotension, and anticholinergic effects; lower EPS risk.
Haloperidol is high-potency with high EPS risk, low sedation, and fewer autonomic effects

Question 2

Why do antipsychotics cause Parkinson-like side effects, and why can Parkinson’s drugs cause psychosis?

Answer 2

Antipsychotics block D2 receptors, mimicking dopamine deficiency like in Parkinson’s.

Parkinson’s drugs increase dopamine, and excessive dopamine can trigger or worsen schizophrenia symptoms like hallucinations.

Question 3

What are the signs of Acute dystonia as an extrapyramidal symptom (EPS), and how can it be managed?

Answer 3

• Acute dystonia: Muscle spasms
• treat with anticholinergics (benztropine or diphenhydramine)

Question 4

What are the signs of Parkinsonism as an extrapyramidal symptom (EPS), and how can it be managed?

Answer 4

• Parkinsonism: Tremor, rigidity
• treat with anticholinergics and amantadine; may resolve spontaneously
• If treatment unsuccessful, may need to change patient to 2nd gen antipsychotic

Question 5

What are the signs of Akathisia as an extrapyramidal symptom (EPS), and how can it be managed?

Answer 5

• Akathisia: Restlessness
• Treat with beta-blockers, benzodiazepines, or dose reduction
• Can alternatively switch to a low-potency 1st-gen antipsychotic

Question 6

What are the signs of Tardive dyskinesia as an extrapyramidal symptom (EPS), and how can it be managed?

Answer 6

• Tardive dyskinesia: Involuntary facial/body movements
• prevention is key, treatment is difficult and may be irreversible

Question 7

What is neuroleptic malignant syndrome (NMS), and how is it managed?

Answer 7

A rare, life-threatening reaction with muscle rigidity, high fever, BP instability, and altered mental status.

Stop antipsychotic immediately, give IV fluids, cooling, and treat with dantrolene or bromocriptine.

Question 8

What are the key differences between high- and low-potency FGAs?

Answer 8

Both block D2 receptors.

High-potency (e.g., haloperidol) causes more EPS but less sedation, hypotension, and anticholinergic effects.

Low-potency (e.g., chlorpromazine) causes fewer EPS but more sedation and autonomic side effects.

Question 9

Why is clozapine not a first-line treatment for schizophrenia, and what monitoring is required?

Answer 9

Clozapine is highly effective but can cause fatal agranulocytosis. Requires weekly WBC monitoring.

Patients must report infection signs, avoid other bone marrow suppressants, and be monitored for seizures, metabolic issues, and orthostatic hypotension.