Hydroxyzine Dosing and Usage
Recommended Dosages
For anxiety in adults, hydroxyzine should be dosed at 50-100 mg four times daily, while for pruritus (itching), the recommended dose is 25 mg three to four times daily. 1
Anxiety Treatment
- Standard adult dosing: 50-100 mg four times daily for symptomatic relief of anxiety and tension 1
- Alternative nighttime strategy: 10-50 mg at bedtime can be used as adjunctive therapy to non-sedating antihistamines during the day 2
- Pediatric dosing: Children under 6 years receive 50 mg daily in divided doses; children over 6 years receive 50-100 mg daily in divided doses 1
Pruritus (Itching) Treatment
- Adult dosing: 25 mg three to four times daily for allergic conditions including chronic urticaria, atopic dermatitis, and contact dermatoses 1
- Bedtime dosing strategy: 10-50 mg at bedtime is particularly effective when combined with non-sedating antihistamines during the day for urticaria patients 2, 3
- Pediatric dosing: Same as anxiety dosing—50 mg daily in divided doses for children under 6 years; 50-100 mg daily in divided doses for children over 6 years 1
Preoperative Sedation
- Adults: 50-100 mg as premedication and following general anesthesia 1
- Children: 0.6 mg/kg of body weight 1
Special Population Adjustments
Renal Impairment
- Moderate renal insufficiency (creatinine clearance 10-20 mL/min): Reduce dose by half 2, 3
- Severe renal impairment (creatinine clearance <10 mL/min): Avoid hydroxyzine entirely 3
Hepatic Impairment
Elderly Patients
- Lower doses recommended due to increased risk of sedative effects and anticholinergic side effects 2
- Older adults with pre-existing conditions (prostatic hypertrophy, elevated intraocular pressure, cognitive impairment) are at particularly high risk for adverse effects 2
Pregnancy
- Contraindicated in early pregnancy 2, 3
- If antihistamine therapy is necessary during pregnancy, chlorphenamine is preferred due to its long safety record 3
Treatment Duration and Clinical Considerations
Duration of Use
- Short-term use preferred: 2-4 weeks for mild to moderate symptoms 2
- Extended monotherapy not recommended due to concerns about reduced concentration and performance 2
- Transition to non-sedating antihistamines for long-term management 2
Efficacy Timeline
- Onset of anxiolytic effect: Significant improvement begins within the first week of treatment 4, 5
- Sustained efficacy: Maintained throughout 4-12 weeks of treatment without rebound anxiety upon discontinuation 4, 5
- Antihistamine effect: Universal histamine skin test suppression maintained the following morning with bedtime dosing 6
Important Safety Considerations
Sedation Profile
- Hydroxyzine causes 80% sedation rates, higher than diphenhydramine (50%) and promethazine (60-73%) 2
- Sleepiness occurs in approximately 28% of patients, typically appearing during the first week and progressively diminishing with continued treatment 4
- Bedtime dosing strategy minimizes daytime psychomotor impairment while maintaining therapeutic efficacy 6
Drug Interactions
- Avoid concomitant use with other CNS depressants (benzodiazepines, opioids, alcohol) as this enhances performance impairment and sedation 2, 3
Common Side Effects
- Drowsiness/sleepiness (28% vs 14% placebo) 4
- Dry mouth (14% vs 5% placebo) 4
- Weight gain (12% vs 10% placebo) 4
- Loss of concentration (9% vs 8% placebo) 4
Combination Therapy
- For urticaria not responding to hydroxyzine alone: Addition of an H2-antagonist (such as cimetidine) may provide better control 3
- For steroid-refractory pruritus: Hydroxyzine 10-25 mg four times daily or at bedtime can be combined with topical corticosteroids 2
Clinical Advantages
- No organ toxicity or dependency documented in clinical experience 7
- Anticholinergic effects provide better control of rhinorrhea compared to second-generation antihistamines 2
- Cost-effective alternative to benzodiazepines for GAD with comparable efficacy 5
- No withdrawal symptoms or rebound anxiety after abrupt discontinuation 4, 5