Table 2.

Antipsychotic Medications Used Clinically in the Treatment of Delirium^*

Medication	Dose Range	Route of Administration	Adverse Effects	Comments
Typical antipsychotics
Haloperidol	0.5-2 mg every 2 to 12 hours	PO, IV, IM, SC	Extrapyramidal adverse effects can occur at higher doses. Monitor QT interval on ECG.	Remains the gold standard therapy for delirium. May add lorazepam (0.5-1 mg every 2 to 4 hours) for agitated patients.
Chlorpromazine	12.5-50 mg every 4 to 6 hours	PO, IV, IM, SC, PR	More sedating and anticholinergic adverse effects compared with haloperidol. Monitor blood pressure for hypotension. More suitable for use in ICU settings for closer monitoring of blood pressure.	May be preferred in agitated patients because of its sedative effect.
Atypical antipsychotics
Olanzapine	2.5-5 mg every 12 to 24 hours	PO,† IM	Sedation is the main dose-limiting adverse effect in short-term use.	Older age, pre-existing dementia, and hypoactive subtype of delirium have been associated with poor response.
Risperidone	0.25-1 mg every 12 to 24 hours	PO†	Extrapyramidal adverse effects can occur with doses > 6 mg/d. Orthostatic hypotension.	May be associated with orthostatic hypotension.
Quetiapine	12.5-100 mg every 12 to 24 hours	PO	Sedation, orthostatic hypotension.	Sedating effects may be helpful in patients with sleep-wake cycle disturbance.
Ziprasidone	10-40 mg every 12 to 24 hours	PO, IM	Monitor QT interval on ECG.	The literature on QT prolongation with ziprasidone makes it the least preferred agent in the medically ill.
Aripiprazole	5-30 mg every 24 hours	PO,† IM	Monitor for akathisia.	Evidence is limited. Might be more efficacious in patients with hypoactive subtype than the hyperactive subtype.

Abbreviations: ICU, intensive care unit; IM, intramuscular; IV, intravenous; PO, oral; PR, per rectum; SC, subcutaneous.

^*Adapted from Breitbart and Alici.⁷

^†Risperidone, olanzapine, and aripiprazole are available in orally disintegrating tablets.