Consultation-Liaison — Pharmacological Control of Dangerous Agitation in ICU Delirium
A 78-year-old woman in the intensive care unit, two days after emergency bowel surgery and not intubated, wakes acutely confused and severely agitated, pulling at lines and striking nurses. Oxygenation, glucose and analgesia are adequate and the bladder is empty. Reorientation and physical measures have failed, and she spits out tablets. QTc is 430 ms. Which medication is most appropriate?
- A.Haloperidol 1 mg intravenouslyCorrect
- B.Olanzapine 5 mg orally
- C.Lorazepam 2 mg intravenously
- D.Diphenhydramine 25 mg intravenously
Explanation
Acute confusion with agitation after surgery in an older patient is hyperactive delirium. Treatment starts with the cause and with non-drug measures, and the Society of Critical Care Medicine 2018 guideline advises against routine antipsychotics for delirium itself. When agitation threatens the safety of the patient or staff and non-drug measures have failed, a short course of an antipsychotic is accepted, and haloperidol given parenterally works within minutes in someone who will not swallow. Olanzapine is a reasonable alternative for a cooperative patient, but an oral tablet is useless when she spits it out and the danger is immediate. Benzodiazepines such as lorazepam deepen and prolong delirium in older adults and are kept for alcohol or benzodiazepine withdrawal and for seizures. Diphenhydramine is strongly anticholinergic and worsens confusion. Intravenous haloperidol carries a dose-related risk of QT prolongation and torsades de pointes, so a baseline QTc, potassium and magnesium should be checked and the electrocardiogram repeated. In older adults start low (0.5 to 1 mg) and repeat or titrate cautiously, and stop the drug once the danger has passed.
Why each option
- A.
- Correct. Low-dose parenteral haloperidol, titrated, acts quickly in dangerous delirium-related agitation after non-drug measures fail, with QTc monitoring during use.
- B.
- Oral olanzapine suits a cooperative patient, but she refuses tablets and the danger to her and the staff is immediate.
- C.
- Benzodiazepines worsen and prolong delirium in older patients and are reserved for alcohol or sedative withdrawal and seizures.
- D.
- Diphenhydramine is strongly anticholinergic, so it aggravates confusion and agitation in older patients with delirium.
Reference: SCCM PADIS Guideline (Devlin et al., Crit Care Med 2018); NICE CG103 Delirium (updated 2023); UpToDate — Delirium and acute confusional states: prevention, treatment, and prognosis
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