Nursing care
Second-generation antipsychotics: metabolic risk, QT effects and dementia warning
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated October 2026
Short answer
Second-generation antipsychotics such as olanzapine, quetiapine and risperidone cause fewer movement disorders than typical agents but carry a higher risk of metabolic syndrome: weight gain, raised glucose and abnormal lipids. Nurses track weight and metabolic labs, watch for orthostatic hypotension and QT risk, and recognise the boxed warning of increased mortality in older adults with dementia-related psychosis.
How atypicals differ from typical antipsychotics
Both generations block dopamine receptors, but second-generation agents also act on serotonin and other receptors. As a class they carry a lower likelihood of involuntary movement disorders than first-generation drugs. The trade-off is a greater risk of metabolic syndrome, described as excess abdominal fat, insulin resistance, dyslipidaemia and hypertension.
Lower movement risk is not zero risk. Tardive dyskinesia, neuroleptic malignant syndrome and akathisia can still occur, and the quetiapine label lists tardive dyskinesia among its warnings. Exam questions often test whether candidates assume atypicals are free of movement effects. Keep screening movements while adding the metabolic surveillance that defines this class.
Metabolic monitoring: weight, glucose and lipids
Atypical antipsychotics have been associated with hyperglycaemia, dyslipidaemia and weight gain. The quetiapine label advises monitoring for thirst, frequent urination, increased hunger and weakness, checking glucose regularly in people with or at risk of diabetes, testing fasting lipids at the start and periodically, and monitoring weight. Olanzapine guidance also notes increased appetite and weight gain.
Record a baseline before or soon after starting, then trend weight, waist measurement, blood pressure, glucose and lipids according to local protocol. Report rapid weight gain or symptoms of high blood sugar rather than waiting for the next scheduled review. Pair monitoring with practical support on meals, activity and sleep, since adherence often falls when weight gain is distressing.
Some patients find it hard to engage with weight and diet discussions while unwell. Keep the conversation practical and non-judgemental, focusing on one or two achievable changes such as regular meals, fewer sugary drinks or a short daily walk. Involve dietitians and community teams where available, and share the trend with the prescriber, who may consider a different agent if metabolic changes progress despite support.
Cardiac effects, orthostasis and blood counts
Several antipsychotics in both generations can prolong the QT interval, including olanzapine and risperidone, raising the risk of serious arrhythmias. Ask about palpitations, fainting, family history of sudden death and other QT-prolonging medicines, and report electrolyte problems such as low potassium. An ECG may be ordered when risk factors exist.
Quetiapine can cause orthostatic hypotension with dizziness, fast heart rate and fainting, especially during early dose titration, and these can lead to falls. Teach slow position changes and assess fall risk. Leukopenia, neutropenia and agranulocytosis are listed warnings, so report fever or sore throat. The quetiapine label also recommends lens examination for cataracts during long-term treatment.
The dementia warning and suicidality
Older adults with dementia-related psychosis treated with antipsychotics have an increased risk of death, and these drugs are not approved for that use. When an older patient with dementia is prescribed one for behaviour, the nurse checks the indication, documents non-drug approaches tried, and monitors closely for sedation, falls, swallowing problems and infection.
Quetiapine, which is also used for bipolar depression, carries an additional boxed warning about suicidal thoughts and behaviours in children, adolescents and young adults taking antidepressant treatment. Ask directly about suicidal thinking at the start and after dose changes. Teach families to report sudden changes in mood, agitation or talk of self-harm.
Worked exam-style scenario
Imagine a hypothetical patient three months into olanzapine therapy who has gained noticeable weight and now reports intense thirst and getting up several times at night to pass urine. Options include reassuring that weight gain is expected, advising a stricter diet only, stopping the medicine independently, or reporting the symptoms and requesting a glucose check.
Reporting and requesting a glucose check is the strongest answer because thirst and frequent urination suggest hyperglycaemia, a recognised metabolic effect. Reassurance misses a possible new diabetes. Stopping independently risks relapse and is not a nursing decision. A comparison item might ask which class has the higher metabolic risk; the answer is second-generation agents.
Sources and further reading
DailyMed: SEROQUEL (quetiapine) prescribing information. Dementia and suicidality boxed warnings, metabolic monitoring, orthostatic hypotension, falls, neutropenia, cataracts and tardive dyskinesia.
MSD Manual Professional: Schizophrenia. Lower movement disorder risk but higher metabolic syndrome risk with second-generation agents, and QT prolongation across both classes.
MedlinePlus: Olanzapine. Increased appetite and weight gain, high blood sugar history and dementia-related warning.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our mental health practice questions are the closest set to what this page covers.
Common questions
Do second-generation antipsychotics cause tardive dyskinesia?
They are less likely to cause movement disorders than typical antipsychotics, but tardive dyskinesia can still occur, so movement screening continues alongside metabolic monitoring.
Which labs are monitored with atypical antipsychotics?
Glucose and fasting lipids are checked at baseline and periodically, alongside weight. Blood counts are reviewed when there is a history of low white cells or symptoms of infection.
Why are antipsychotics risky in older adults with dementia?
Older adults with dementia-related psychosis have an increased risk of death when treated with antipsychotics, and these drugs are not approved for that use.
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