Medication errors can get ugly in a hurry. I was prompted to write this example as I came across a situation recently where an elderly patient received a schizophrenic patient’s high-dose antipsychotic. This high dose antipsychotic error resulted in an ICU stay for the patient who incorrectly received the antipsychotic. Here’s what to look out for when a high-dose antipsychotic is part of a wrong resident medication error.
Giving a high dose of quetiapine (Seroquel), such as 300 mg, to an elderly patient in error carries several serious risks due to age-related pharmacokinetic changes, comorbidities, and increased sensitivity to central nervous system effects. Older adults generally require much lower starting doses, and rapid exposure to a high dose can quickly lead to harm.
Orthostatic hypotension (excellent board exam nugget) is a major concern at higher doses of quetiapine. The drug’s alpha-1 blocking effects can cause sudden drops in blood pressure when standing, leading to dizziness, syncope, and falls. Elderly patients are particularly vulnerable, especially if they are dehydrated or taking antihypertensives, diuretics, or other blood pressure–lowering medications. Cardiovascular monitoring in a situation like this is essential.
Another one of the primary risks is excessive sedation and cognitive impairment. A 300 mg dose can cause profound drowsiness, confusion, delirium, and impaired judgment, which significantly increases the risk of falls and fractures. In an elderly patient, even a single fall can result in major morbidity, including hip fractures, intracranial bleeding, and loss of independence.
High-dose quetiapine also increases the risk of cardiac adverse effects. QT interval prolongation can occur, raising the risk of arrhythmias, particularly in patients with underlying heart disease, electrolyte abnormalities, or concurrent QT-prolonging medications. Tachycardia is also more likely at higher doses and may be poorly tolerated in frail patients.
Extrapyramidal symptoms and worsening mobility are additional risks, even though quetiapine is considered lower risk for these effects compared to other antipsychotics. At higher doses, elderly patients may experience rigidity, tremor, or akathisia, which can further impair gait and increase fall risk.
Finally, there are significant safety concerns when quetiapine is used in elderly patients with dementia-related psychosis. Antipsychotics, including quetiapine, carry a boxed warning for increased mortality in this population. Administering a high dose unintentionally magnifies this risk and represents a serious medication safety event.
In practice, quetiapine should be started at very low doses in older adults, often 12.5 to 25 mg, with slow titration and close monitoring. A high dose antipsychotic error should prompt immediate clinical assessment, monitoring for sedation, blood pressure changes, cardiac effects, falls, possible ER admission, and a thorough review of medication safety processes to prevent recurrence.
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