What is the recommended dose of hydroxyzine (antihistamine) for allergic rhinitis?

Hydroxyzine Dose for Allergic Rhinitis

Hydroxyzine should generally NOT be used for allergic rhinitis due to significant safety concerns, but if prescribed, the typical adult dose is 10 mg daily (up to 150 mg/day was tolerated in research), with pediatric dosing of 2.5 mg once or twice daily for ages 2-5 years and 5-10 mg/day for ages 6-12 years. 1

Why Hydroxyzine Is Not Recommended

Second-generation antihistamines are strongly preferred over hydroxyzine (a first-generation antihistamine) for allergic rhinitis treatment. 1, 2

Critical Safety Concerns with Hydroxyzine

• Drivers taking hydroxyzine are 1.5 times more likely to be responsible for fatal automobile accidents, and this impairment worsens significantly with cellular phone use 1
• Performance impairment can exist without subjective awareness of drowsiness—patients may deny sedation while still experiencing measurable cognitive and motor deficits 1
• Workers taking first-generation antihistamines like hydroxyzine exhibit impaired work performance and productivity and are more likely to be involved in occupational accidents 1
• Children may experience impaired learning and school performance 1

Additional Adverse Effects

• Anticholinergic effects including dry mouth, constipation, urinary retention, and increased risk of narrow-angle glaucoma 1
• Older adults are particularly vulnerable to psychomotor impairment, falls leading to fractures and subdural hematomas, and anticholinergic complications 1
• Paradoxical CNS stimulation may occur, particularly in children 1

Dosing Information (If Hydroxyzine Must Be Used)

Adult Dosing

• Standard dose: 10 mg daily 1
• Age 12-65 years: 10 mg/day 1
• Age 66-76 years: 5-10 mg/day 1
• Age ≥77 years: 5 mg/day 1
• Research has shown tolerance up to 150 mg/day when slowly titrated, though drowsiness and dry mouth were frequent initially 3

Pediatric Dosing

• Age 2-5 years: 2.5 mg once or twice daily 1
• Age 6-12 years: 5-10 mg/day 1

Important Clinical Pitfalls

The Bedtime-Only Strategy Does NOT Work

A common misconception is that taking hydroxyzine only at bedtime avoids daytime impairment—this is FALSE. 1

• First-generation antihistamines and their metabolites have prolonged plasma half-lives, and their end-organ effects persist longer than plasma levels of the parent compound 1
• Bedtime dosing is still associated with significant next-day drowsiness, decreased alertness, and performance impairment 1
• An AM/PM dosing regimen combining a second-generation agent in the morning with hydroxyzine at night is NOT a preferred strategy 1

Contraindications and Cautions

• Avoid in patients taking other CNS-active substances (alcohol, sedatives, hypnotics, antidepressants), as these further enhance performance impairment 1
• Use extreme caution in older adults with comorbid conditions like increased intraocular pressure, benign prostatic hypertrophy, or preexisting cognitive impairment 1
• Avoid in occupations requiring alertness (driving, operating machinery, safety-sensitive work) 1

Preferred Alternatives

Second-generation antihistamines are the appropriate choice for allergic rhinitis, as they are associated with less or no tendency for sedation, performance impairment, or anticholinergic effects. 1, 2

When Anticholinergic Effects Are Desired

If anticholinergic properties are specifically needed (e.g., persistent rhinorrhea despite second-generation antihistamine and intranasal corticosteroid), a topical anticholinergic agent (intranasal ipratropium) is preferred over systemic agents like hydroxyzine because it lacks sedation and performance impairment potential. 1

Historical Context

While one 1979 study showed hydroxyzine 150 mg/day was effective for seasonal allergic rhinitis symptoms 3, this research predates modern understanding of antihistamine-related impairment and the availability of safer second-generation alternatives. The consensus among allergy experts is that relatively nonimpairing second-generation antihistamines (loratadine, desloratadine, cetirizine, fexofenadine) are preferred over older agents like hydroxyzine. 2