Management of Delirium

Pharmacological Approaches

The American Society of Clinical Oncology recommends antipsychotics as the mainstay of pharmacological treatment for delirium with agitation, with olanzapine and quetiapine as first-line options 1
The European Society for Medical Oncology suggests starting with low doses of olanzapine (2.5-5 mg orally or subcutaneously) and quetiapine (25 mg immediate release orally, given every 12 hours if scheduled dosing is required) 1
Haloperidol is recommended as a second-line option, with a starting dose of 0.5-1 mg orally or subcutaneously for acute management, and lower doses in older or frail patients 1
Benzodiazepines are only recommended as monotherapy for alcohol or benzodiazepine withdrawal delirium, or as crisis medication for severe agitation unresponsive to antipsychotics, with lorazepam as a preferred option (0.25-0.5 mg subcutaneously or intravenously in elderly patients) 1

The American College of Physicians recommends addressing underlying causes of delirium first, ensuring effective communication and orientation measures, providing adequate lighting and familiar objects to reduce confusion, and treating contributing factors such as pain, constipation, or urinary retention 2

Medications for delirium should be started on an as-needed (PRN) basis initially, with regular scheduled dosing only implemented for persistent distressing symptoms and for the shortest time possible 1, 3
No medication is currently licensed specifically for delirium management worldwide, and antipsychotics themselves can potentially cause or worsen delirium, requiring careful monitoring 1, 3, 2
The National Comprehensive Cancer Network recommends monitoring for common side effects of antipsychotics, including extrapyramidal symptoms, sedation, orthostatic hypotension, and QTc prolongation 1
Escitalopram carries risks that would be problematic in delirium, including QT prolongation at higher doses, potential for drug-drug interactions via CYP450 pathways, and contribution to serotonin syndrome if combined with other serotonergic medications 4

The American Society of Clinical Oncology recommends using quetiapine 25 mg orally every 12 hours as an alternative to olanzapine, with a lower risk of extrapyramidal side effects and beneficial sedation for agitated patients 5
For elderly or frail patients, the European Society for Medical Oncology suggests reducing starting doses of olanzapine to 2.5 mg or haloperidol to 0.25-0.5 mg, and avoiding benzodiazepines as monotherapy due to increased fall risk, respiratory depression, and paradoxical agitation 5, 6
The American Geriatrics Society recommends using haloperidol 0.5-1 mg orally or subcutaneously as a second-line option, but advises against its use in patients with Parkinson's disease or Lewy body dementia due to high risk of extrapyramidal side effects 6

The neurobiology of delirium involves neuroinflammation, neuronal injury, and neurotransmitter imbalances—particularly cholinergic and dopaminergic systems—not serotonin 5-HT3 pathways, according to the Alzheimer's Association 7