Hydroxyzine HCl Dosing for Adults
For anxiety in adults, hydroxyzine HCl should be dosed at 50-100 mg four times daily, while for pruritus due to allergic conditions, the recommended dose is 25 mg three to four times daily. 1
Anxiety Management
The FDA-approved dosing for symptomatic relief of anxiety and tension associated with psychoneurosis is 50-100 mg four times daily in adults. 1
Hydroxyzine demonstrated statistically significant anxiolytic efficacy beginning in the first week of treatment at 50 mg/day, with benefits maintained throughout 4 weeks and persisting after abrupt discontinuation without rebound anxiety or withdrawal symptoms. 2
In a 3-month controlled trial, hydroxyzine 50 mg/day showed sustained efficacy comparable to bromazepam 6 mg/day and superior to placebo, making it an effective alternative to benzodiazepine prescription for generalized anxiety disorder. 3
Pruritus/Allergic Conditions Management
For management of pruritus due to allergic conditions such as chronic urticaria, atopic dermatitis, and contact dermatoses, the FDA recommends 25 mg three to four times daily in adults. 1
When used as an adjunct to non-sedating antihistamines for urticaria, hydroxyzine 10-50 mg at bedtime can help patients sleep better, though it provides little additional clinical effect on urticaria if the H1 receptor is already saturated by daytime antihistamines. 4
For steroid-refractory pruritus, hydroxyzine 10-25 mg four times daily or at bedtime can be combined with topical corticosteroids. 5
Critical Dosing Adjustments
Renal Impairment
In moderate renal impairment (creatinine clearance 10-20 mL/min), the hydroxyzine dose must be reduced by half. 4, 6
Hydroxyzine should be avoided entirely in severe renal impairment (creatinine clearance <10 mL/min). 4, 6
Hepatic Impairment
- Hydroxyzine must be avoided in severe liver disease because its sedating effects are inappropriate and potentially dangerous in this population. 4, 6, 5
Elderly Patients
Elderly adults are at high risk for side effects from hydroxyzine, particularly sedation and anticholinergic effects, and should be started at the low end of the dosing range. 5
Hydroxyzine is specifically listed as a medication to deprescribe in older adults due to fall risk and CNS impairment. 5
Despite these concerns, a single 25 mg dose of hydroxyzine preserved memory and attention in elderly subjects, unlike lorazepam which caused clear memory deficiencies. 7
Administration Strategies
Adjusting the timing of medication can be helpful to ensure highest drug levels are obtained when symptoms are anticipated. 4
When treatment is initiated by intramuscular route, subsequent doses may be administered orally, and dosage should be adjusted according to the patient's response to therapy. 1
Common Pitfalls and Contraindications
Pregnancy
Hydroxyzine is specifically contraindicated during early pregnancy. 6, 5
If antihistamine therapy is necessary during pregnancy, chlorphenamine is often preferred due to its long safety record. 6
Drug Interactions
Avoid concomitant use with other CNS depressants as this enhances performance impairment and sedation. 5
Hydroxyzine should not be taken with other sedative or central nervous system depressant medications. 5
Side Effect Profile
The most common side effect is transient sleepiness (28% vs 14% with placebo), which typically appears during the first week and progressively diminishes during continued treatment. 2
Hydroxyzine causes 80% sedation rates compared to 50% with diphenhydramine and 60-73% with promethazine. 5
Other side effects include weight gain (12%), dry mouth (14%), loss of concentration (9%), and insomnia (9%). 2
Duration of Use
Prolonged use as monotherapy is not recommended due to concerns about reduced concentration and performance. 5
For mild to moderate itching, hydroxyzine can be used for 2-4 weeks, with transition to non-sedating antihistamines recommended for long-term management. 5
Special Clinical Considerations
Hydroxyzine's sedating and anticholinergic properties make it inappropriate for use in delirium management. 5
The anticholinergic effects provide better control of rhinorrhea compared to second-generation antihistamines. 5
Before oral food challenge testing, hydroxyzine should be discontinued 7-10 days prior to avoid interference with interpretation. 4