Hydroxyzine Dosing Recommendations
The recommended dosing for hydroxyzine as an antihistamine for pruritus and allergic conditions is 25 mg three to four times daily for adults, while children under 6 years should receive 50 mg daily in divided doses, and children over 6 years should receive 50-100 mg daily in divided doses. 1
Adult Dosing
Pruritus and Allergic Conditions
- 25 mg three to four times daily (total daily dose: 75-100 mg) 1
- For urticaria management, hydroxyzine 10-25 mg three times daily is commonly used as initial therapy 2
- When used at bedtime as a sedating antihistamine to complement daytime non-sedating antihistamines, 10-50 mg can be effective for helping patients sleep better 3
Anxiety Management (if relevant)
- 50-100 mg four times daily (higher than antihistamine dosing) 1
- Lower doses of 50 mg/day have shown significant anxiolytic effects with acceptable side effect profiles 4
Pediatric Dosing
- Children under 6 years: 50 mg total daily dose, divided throughout the day 1
- Children over 6 years: 50-100 mg total daily dose, divided throughout the day 1
- For atopic dermatitis in children, 0.7 mg/kg three times daily has been shown to be as effective as 1.4 mg/kg three times daily with significantly less sedation 5
Dosing Considerations
Renal Impairment
- The dose of hydroxyzine should be halved in patients with moderate renal impairment 3
- Hydroxyzine should be avoided in severe renal impairment (creatinine clearance <10 mL/min) 3
Hepatic Impairment
- Hydroxyzine should be avoided in severe liver disease due to its sedating effects 3
Pregnancy
- Hydroxyzine is specifically contraindicated during early pregnancy 3
- If antihistamine therapy is necessary during pregnancy, chlorphenamine is often preferred due to its long safety record 3
Administration Strategies
- Evening dosing of hydroxyzine (50 mg at bedtime) can help minimize daytime sedation while maintaining antihistaminic effects 6
- For patients with urticaria not responding to hydroxyzine alone, addition of an H2-antagonist (such as cimetidine) may provide better control 3, 2
Side Effects and Monitoring
- Common side effects include sedation/drowsiness (28%), dry mouth (14%), and weight gain (12%) 4
- Hydroxyzine significantly prolongs both simple and choice reaction times, affecting performance of critical tasks 7
- Sedation typically appears during the first week of treatment and may progressively diminish with continued use 4
- No correlation has been found between subjective symptoms and objective performance impairment, suggesting patients may be impaired even when not feeling drowsy 7
Clinical Pearls
- Hydroxyzine can be particularly useful when added at night to a non-sedating antihistamine regimen for patients with urticaria 3
- For pruritus management in dermatological conditions, hydroxyzine's sedating properties can be beneficial at bedtime 3
- Avoid concomitant use with other CNS depressants as this may enhance performance impairment 3
- Tolerance to the sedative effects may develop over time, but tolerance to the antipruritic effects is less common 6, 5