What is the dosage and usage of Hydroxyzine for anxiety, itching, or nausea in adults and the elderly?

Hydroxyzine Dosing and Usage

Direct Dosing Recommendations

For anxiety and tension in adults, hydroxyzine should be dosed at 50-100 mg four times daily, while for pruritus the dose is 25 mg three to four times daily, according to FDA labeling. 1

Anxiety Treatment Dosing

• Adults: 50-100 mg four times daily for symptomatic relief of anxiety and tension associated with psychoneurosis 1
• Elderly patients: Start with lower doses due to increased sensitivity to anticholinergic effects and sedation, though specific elderly dosing is not provided in FDA labeling 1
• Children under 6 years: 50 mg daily in divided doses 1
• Children over 6 years: 50-100 mg daily in divided doses 1

Pruritus (Itching) Treatment Dosing

• Adults: 25 mg three to four times daily for management of pruritus due to allergic conditions such as chronic urticaria, atopic dermatitis, and contact dermatoses 1
• Children under 6 years: 50 mg daily in divided doses 1
• Children over 6 years: 50-100 mg daily in divided doses 1

Preoperative Sedation/Nausea

• Adults: 50-100 mg as premedication and following general anesthesia 1
• Children: 0.6 mg/kg of body weight 1

Critical Safety Considerations in Elderly Patients

Hydroxyzine should be avoided in elderly patients whenever possible due to significant risks of cognitive decline, falls, and anticholinergic toxicity. 2

• First-generation antihistamines like hydroxyzine are associated with cognitive decline, particularly worrisome in elderly populations 2
• Hydroxyzine carries anticholinergic effects including dry mouth, urinary retention, constipation, and increased intraocular pressure 2
• The American Geriatrics Society recommends avoiding first-generation antihistamines in older adults due to strong anticholinergic and sedative properties that increase risk of falls, fractures, subdural hematomas, cognitive impairment, and delirium 3

Clinical Positioning and Efficacy

For Anxiety

Hydroxyzine is NOT a first-line treatment for generalized anxiety disorder and is notably absent from major anxiety treatment guidelines (NICE, S3, Canadian CPG, AACAP 2020). 4

• SSRIs and SNRIs remain first-line treatments for GAD based on robust evidence 4
• Hydroxyzine at 50 mg/day produces statistically significant anxiolytic effect beginning in the first week of treatment 5
• A Cochrane review concluded that despite being more effective than placebo, hydroxyzine cannot be recommended as a reliable first-line treatment in GAD due to high risk of bias in studies and small sample sizes 6
• Hydroxyzine demonstrated greater and more rapid cognitive improvement compared to lorazepam in one controlled trial 7

For Pruritus

Hydroxyzine is effective for histamine-mediated pruritus and dermatologic manifestations in conditions like mast cell activation syndrome. 2

• H1 receptor blockers like hydroxyzine reduce dermatologic manifestations including flushing and pruritus 2
• Hydroxyzine works better as prophylactic treatment than acute treatment because once symptoms are apparent, it is too late to block histamine binding to receptors 2

For Nausea

Hydroxyzine is NOT recommended for nausea based on available evidence, as antiemetic guidelines do not include it as a preferred agent. 2

• Antiemetic guidelines recommend 5-HT3 antagonists (ondansetron, granisetron) with or without dexamethasone for nausea prophylaxis 2
• Benzodiazepines like lorazepam and alprazolam are recommended for anticipatory nausea, not hydroxyzine 2

Adverse Effects Profile

The most common side effect is transient sleepiness, occurring in 28% of patients, which typically appears during the first week and progressively diminishes. 5

• Sleepiness/drowsiness: 28% vs 14% with placebo 5
• Dry mouth: 14% vs 5% with placebo 5
• Weight gain: 12% vs 10% with placebo 5
• Loss of concentration: 9% vs 8% with placebo 5
• Insomnia: 9% vs 6% with placebo 5
• Hydroxyzine causes performance impairment even when patients don't subjectively feel drowsy 8

Dosing Strategy to Minimize Side Effects

Bedtime dosing of hydroxyzine (50 mg at bedtime) can mitigate reaction time degradation and adverse subjective symptoms while maintaining antihistamine efficacy the following morning. 8

• Evening dosing maintains H1-receptor antagonism the following morning 8
• Bedtime dosing alleviates prolongation of reaction times seen with divided doses 8
• However, bedtime dosing does not completely eliminate subjective symptoms like drowsiness, dry mouth, and irritability 8

Absolute Contraindications

Hydroxyzine is contraindicated in early pregnancy per UK manufacturer guidelines and should be avoided in severe liver disease. 4

• Avoid in early pregnancy 4
• Avoid in severe liver disease due to inappropriate sedating effects 4
• Use with extreme caution in patients with benign prostatic hypertrophy, elevated intraocular pressure, or cognitive impairment due to anticholinergic effects 2

Key Clinical Pitfalls to Avoid

• Do not use hydroxyzine as a first-line agent for anxiety when SSRIs, SNRIs, or buspirone are appropriate alternatives 4
• Do not prescribe hydroxyzine to elderly patients at risk of falls without considering safer second-generation antihistamines like fexofenadine 3
• Do not assume hydroxyzine is effective for nausea based on its sedative properties alone, as evidence does not support this indication 2
• Do not use hydroxyzine as PRN chemical restraint in psychiatric settings, as this practice is prohibited per JCAHO standards 4
• Adjust dosage according to patient response rather than using fixed maximum doses, as FDA labeling recommends 1