Antipsychotics: extrapyramidal effects and the AIMS, NMS, metabolic monitoring and clozapine safety
- Safe practice
The nurse watches antipsychotics for abnormal movements, fever with rigidity, weight and sugar changes and, with clozapine, infection and heart signs.
What it is
First-generation antipsychotics block dopamine strongly and often cause extrapyramidal effects and tardive dyskinesia. Second-generation drugs cause fewer movement problems but more weight gain and metabolic syndrome. Any antipsychotic can, rarely, cause neuroleptic malignant syndrome (NMS). Clozapine, used for treatment-resistant schizophrenia, needs regular blood counts because it can lower white cells dangerously, and it can cause seizures, heart inflammation, low blood pressure and severe constipation. The nurse assesses movements, often with the Abnormal Involuntary Movement Scale (AIMS), tracks weight, glucose and lipids, and teaches.
What it requires
- The AIMS (Abnormal Involuntary Movement Scale) is a clinician-rated scale of abnormal involuntary movements, used routinely to screen and follow up the movement effects of antipsychotics such as tardive dyskinesia.
- Baseline weight, waist, blood pressure, glucose and lipids; an ECG when ordered or when QT-prolonging medicines are combined (mhGAP).
- For clozapine: the laboratory schedule for blood counts, and a bowel chart.
- Anticholinergic antiparkinson medicines (for example biperiden) for extrapyramidal effects when prescribed.
Components
- Movement assessment: dystonia, akathisia, parkinsonism, tardive dyskinesia.
- Recognition of NMS and other emergencies (laryngeal dystonia, seizures, agranulocytosis, myocarditis).
- Metabolic and cardiovascular monitoring.
- Teaching and adherence support, including long-acting injections.
How it is applied (and why)
- Record baseline movements and repeat the AIMS at the intervals the protocol sets — early tardive dyskinesia may reverse if the medicine is changed.
- Look for neck or eye spasm, tongue protrusion or difficulty swallowing or breathing in the first days — acute dystonia needs rapid treatment.
- Ask whether the person feels unable to sit still and observe pacing — akathisia is distressing and can be mistaken for more agitation.
- Check temperature, muscle tone, mental state and vital signs when fever or rigidity appear — NMS is rare but can be fatal.
- If NMS is suspected, notify at once, cool, give fluids as ordered and monitor vital signs and electrolytes — early care saves lives.
- Measure weight, waist and blood pressure and take capillary or ordered glucose and lipids — second-generation drugs raise metabolic risk.
- With clozapine, confirm the blood count is current before the dose and ask daily about infection signs and bowel movements.
- Teach to rise slowly, avoid alcohol, report abnormal movements and not stop suddenly — sudden stopping can cause rebound movements and relapse.
In nursing practice
- Older adults with dementia-related psychosis on antipsychotics have a higher risk of death: report any such use to the prescriber.
- Clozapine may need restarting at a low dose if two or more days are missed: report missed doses.
- Smoking can lower clozapine's effect; a change in smoking habits is reported.
- Agitation and hallucinations often settle within days, delusions within weeks; the full effect may take up to six weeks.
Common mistakes
- Calling akathisia «more agitation» and asking for more antipsychotic.
- Waiting for the next round when fever and rigidity appear.
- Weighing the person only at admission.
- Giving clozapine without checking the blood-count schedule.
Test yourself
Think of the answer, then tap the question to see it.
What does the AIMS assess?
Abnormal involuntary movements; nurses use it routinely to screen for and follow movement effects such as tardive dyskinesia in people taking antipsychotics.
Which findings suggest neuroleptic malignant syndrome?
High fever, severe muscle rigidity, confusion or agitation and unstable vital signs; laboratory tests may show high CK and white cells. Notify at once.
Why does clozapine need regular blood counts?
It can cause a severe fall in white blood cells (agranulocytosis), with a risk of serious infection.
Which checks make up metabolic monitoring with second-generation antipsychotics?
Weight and waist, blood pressure, fasting glucose and lipids, before starting and then as ordered.
Connections
Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.
Sources: Nursing: Mental Health and Community Concepts, 11.3: Schizophrenia (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2022); Nursing: Mental Health and Community Concepts, 11.4: Applying the nursing process to schizophrenia (Open RN, Wisconsin Technical College System (CC BY 4.0), LibreTexts, 2022); mhGAP Intervention Guide for mental, neurological and substance use disorders in non-specialized health settings, version 2.0 (World Health Organization (WHO), 2016); Clozapine (drug information) (MedlinePlus, U.S. National Library of Medicine, 2026); Tardive dyskinesia (Medical Encyclopedia) (MedlinePlus, U.S. National Library of Medicine, 2026).
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Representative model, for educational purposes only.