Antipsychotic adverse effects: extrapyramidal, metabolic, cardiac and clozapine-specific
The mechanism and timing of each extrapyramidal syndrome and NMS, why some antipsychotics cause weight gain, diabetes and QT prolongation, and clozapine's neutropenia, myocarditis, gut hypomotility and CYP1A2 interaction with smoking, with Australian monitoring thresholds.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Extrapyramidal syndromes come from nigrostriatal D2 blockade and have a predictable timeline: dystonia, akathisia, parkinsonism, tardive dyskinesia.
- Metabolic harm follows H1 and 5-HT2C blockade: worst with clozapine and olanzapine.
- QT prolongation is hERG (IKr) blockade, dose-dependent and additive.
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Sources
- Clozaril (clozapine) Australian Product Information, sections 4.2 and 4.4 (re-starting after more than 2 days; WBC and ANC monitoring)AU/NZmedsinfo.com.au (sponsor Product Information), July 2026
- Therapeutic Guidelines: PsychotropicAU/NZTherapeutic Guidelines Ltd, 2021
- A new monitoring protocol for clozapine-induced myocarditis based on an analysis of 75 cases and 94 controlsAU/NZAustralian and New Zealand Journal of Psychiatry (Ronaldson, Fitzgerald, Taylor, Topliss and McNeil, 2011;45:458-65), 2011
- Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for the management of schizophrenia and related disordersAU/NZAustralian and New Zealand Journal of Psychiatry (Galletly et al., 2016;50:410-72), 2016
- Atypical antipsychotic drugs and the risk of sudden cardiac deathNew England Journal of Medicine (Ray, Chung, Murray, Hall and Stein, 2009;360:225-35), 2009
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- The Maudsley Prescribing Guidelines in Psychiatry (15th ed.)Wiley-Blackwell (Taylor, Barnes and Young, 2025), 2025
- Last updated
- 14 November 2026
What changed
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