Treatment and prescribing
Antipsychotics
Indications and classes
Used for schizophrenia-spectrum illness, acute mania, psychotic depression and selected severe behavioural symptoms. First-generation agents have stronger D2 blockade; second-generation agents have varied dopamine/serotonin effects. Choice is based on prior response, adverse effects, physical health, formulation and preference—not class alone.
- Merck: FGAs (conventional/typical) vs SGAs (atypical); SGAs may be modestly more effective, though evidence is inconsistent (1).
Before and during treatment
Baseline weight/BMI, waist, BP, glucose/HbA1c, lipids, movement examination, smoking status and ECG/prolactin when indicated. Review response, adherence, sedation, sexual effects, EPS and metabolic change. Avoid unnecessary polypharmacy.
Important emergencies
Neuroleptic malignant syndrome; acute dystonia affecting airway/eyes; severe QT-related symptoms; marked hyperglycaemia; and clozapine fever, chest pain, severe constipation or infection symptoms require urgent protocol-based assessment.
Adverse-effect patterns
EPS and prolactin elevation are more prominent with some agents; weight gain/metabolic effects with others. QT prolongation, orthostasis, anticholinergic effects and lowered seizure threshold vary. Tardive dyskinesia can persist—monitor and act early.
- Metabolic syndrome risk is greater with SGAs than FGAs. QT prolongation and fatal arrhythmia risk are reported with thioridazine, haloperidol, olanzapine, risperidone and ziprasidone (1).
Clozapine and practical prescribing
Clozapine is effective for treatment-resistant schizophrenia and requires specialist initiation, mandated blood monitoring and active management of myocarditis and constipation risks. Use local guidelines for dosing, switching, depot therapy and rapid tranquillisation.
- Long-acting injectable formulations exist for both classes (1).
Last updated from Sen’s notes on 9 October 2026.