How to Choose Intravenous Hydroxyzine for Delirium
How should clinicians decide when intravenous hydroxyzine monotherapy is a reasonable alternative to intravenous haloperidol for delirium?
When a hospitalized patient has delirium and oral administration is difficult, clinicians may need a parenteral option that avoids dopamine D2 blockade. This article provides a narrow monotherapy comparison suggesting intravenous hydroxyzine is a reasonable alternative to intravenous haloperidol in selected inpatients.
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Confirm delirium with structured assessment
Before selecting treatment, confirm that the patient meets the article's definition of delirium with a positive CAM or CAM-ICU result. The study treated the first positive CAM or CAM-ICU day as delirium onset.
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Reserve the intravenous option for patients who cannot take oral treatment
The article states that after the institutional algorithm was introduced, intravenous hydroxyzine was recommended before haloperidol when oral administration was difficult. Use this comparison only in that practical context rather than as a general statement about all delirium treatment.
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Make sure the patient fits a monotherapy scenario
Apply the study findings only when delirium treatment is being given as monotherapy. The analysis excluded patients receiving concomitant antipsychotics, orexin receptor antagonists such as suvorexant or lemborexant, melatonin receptor agonists such as ramelteon, sedative antidepressants such as trazodone or mianserin, oral hydroxyzine or haloperidol, or simultaneous intravenous hydroxyzine and haloperidol.
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Exclude withdrawal-related delirium patterns not studied
Do not generalize this hydroxyzine-versus-haloperidol comparison to benzodiazepine withdrawal delirium or likely alcohol withdrawal delirium. The study excluded patients with benzodiazepine withdrawal delirium and those at high risk of alcohol withdrawal delirium, defined as more than 60 g of pure alcohol per day.
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Use intravenous hydroxyzine as a reasonable alternative to haloperidol
In the study's selected monotherapy cohort, intravenous hydroxyzine was associated with a higher delirium improvement rate than intravenous haloperidol. Improvement occurred in 23.9% of hydroxyzine-treated patients versus 8.5% of haloperidol-treated patients, while mean time to improvement was 7.0 versus 8.2 days and was not significantly different in the primary analysis.
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Use the study's observed dosing range as descriptive practice context
The mean first-day dose in the study was 29.9 mg/day for intravenous hydroxyzine and 3.3 mg/day for intravenous haloperidol. The mean maximum doses were 36.1 mg/day and 4.1 mg/day, respectively; these values describe how monotherapy was used in this retrospective cohort rather than a validated dosing protocol.
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Reassess improvement using the same 3-day endpoint
Judge response using the same outcome definition used in the article. Delirium improvement required CAM or CAM-ICU negativity for 3 consecutive days.
Clinical Considerations
- This was a retrospective single-center study with possible confounding and treatment-selection bias, so the findings are preliminary.
- Only 71 hydroxyzine-treated patients and 82 haloperidol-treated patients met eligibility criteria out of 5,555 patients who developed delirium, limiting generalizability.
- Prescribing patterns changed over time, with haloperidol used in approximately 90% of cases before 2021 and hydroxyzine used in approximately 90% after 2021, creating an era effect.
- The study did not assess adverse events, and the authors advised caution about drowsiness in elderly patients receiving hydroxyzine.
Bottom Line
For hospitalized patients with confirmed delirium who cannot take oral medication and are being treated without other delirium drugs, intravenous hydroxyzine is a reasonable alternative to intravenous haloperidol based on a higher improvement rate in this selected cohort.
