What is the maximum recommended dose of Atarax (hydroxyzine)?

Maximum Dose of Atarax (Hydroxyzine)

The maximum dose of hydroxyzine is 100 mg four times daily (400 mg/day total) for adults when treating anxiety and tension, though doses should be adjusted based on patient response and clinical context. 1

FDA-Approved Maximum Dosing by Indication

For Anxiety and Tension (Psychoneurosis)

• Adults: 50-100 mg four times daily (q.i.d.), which equals a maximum of 400 mg/day 1
• Children under 6 years: 50 mg daily in divided doses 1
• Children over 6 years: 50-100 mg daily in divided doses 1

For Pruritus (Allergic Conditions, Chronic Urticaria)

• Adults: 25 mg three to four times daily (t.i.d. or q.i.d.), which equals a maximum of 100 mg/day 1
• Children under 6 years: 50 mg daily in divided doses 1
• Children over 6 years: 50-100 mg daily in divided doses 1

For Premedication/Sedation

• Adults: 50-100 mg as a single dose 1
• Children: 0.6 mg/kg body weight 1

Critical Dosing Adjustments Required

Renal Impairment

• Moderate impairment (creatinine clearance 10-20 mL/min): Reduce dose by 50% 2, 3
• Severe impairment (creatinine clearance <10 mL/min): Avoid hydroxyzine entirely 2, 3

Hepatic Impairment

• Severe liver disease: Avoid hydroxyzine completely due to inappropriate sedating effects that may precipitate hepatic complications 2, 3

Elderly Patients

• Lower doses are strongly recommended due to increased risk of anticholinergic effects (dry mouth, blurred vision, urinary retention), cognitive impairment, and excessive sedation 3
• The long half-life of 20 ± 4.1 hours leads to drug accumulation with repeated dosing, particularly problematic in elderly patients 3
• Higher doses significantly increase anticholinergic side effects in elderly patients with prostatic hypertrophy, elevated intraocular pressure, or baseline cognitive impairment 3

Absolute Contraindications

Pregnancy

• Hydroxyzine is the only antihistamine specifically contraindicated during early pregnancy, particularly in the first trimester 2, 3
• Should be avoided throughout pregnancy when possible 2

Lactation

• Avoid during breastfeeding 3

Important Clinical Considerations

Timing Optimization

• Bedtime dosing (50 mg at night) can mitigate daytime psychomotor impairment and reaction time degradation while maintaining antihistamine efficacy the following morning 4
• This strategy reduces drowsiness, dry mouth, and irritability compared to divided daytime dosing 4

Drug Interactions

• Discontinue at least 6 days before skin prick testing due to prolonged antihistaminic effects (desloratadine requires the longest discontinuation at 6 days due to 27-hour elimination half-life) 3

Common Pitfalls to Avoid

• Do not exceed 400 mg/day in outpatient settings without close monitoring 1
• Watch for CNS depression: Fatigue, sedation, impaired memory, concentration difficulties, and driving impairment are well-documented 5
• Drowsiness is most prominent during the first week and typically diminishes with continued treatment 6, 7
• Avoid in patients with significant cardiac disease when considering alternative antihistamines like mizolastine 2

Efficacy Timeline

• Anxiolytic effects begin within the first week of treatment at 50 mg/day 6, 7
• Full therapeutic effect is maintained throughout 4-12 weeks of treatment 6, 7
• No rebound anxiety or withdrawal symptoms occur with abrupt discontinuation 6, 7