Hydroxyzine Pamoate vs Atarax: Formulation Differences
Hydroxyzine pamoate and Atarax are NOT the same formulation—Atarax is the brand name for hydroxyzine hydrochloride, while hydroxyzine pamoate is marketed under the brand name Vistaril. 1
Key Formulation Distinctions
- Hydroxyzine hydrochloride (Atarax) and hydroxyzine pamoate (Vistaril) are two different salt forms of the same active drug, hydroxyzine 1
- Both formulations are first-generation antihistamines with identical clinical effects including sedation, antipruritic properties, and anxiolytic activity 2, 1
- The primary difference lies in the salt formulation, which affects absorption characteristics but results in equivalent therapeutic outcomes when dosed appropriately 1
Clinical Applications (Identical for Both Formulations)
For pruritus and allergic conditions:
- Dosing ranges from 10-50 mg, typically given at bedtime when used as a sedating antihistamine in combination with non-sedating antihistamines during the day 1
- Effective for managing pruritus associated with urticaria, atopic dermatitis, and other dermatological reactions 1
For anxiety management:
- Dosing ranges from 10-50 mg, though not considered first-line treatment due to limited high-quality evidence 1
- Hydroxyzine demonstrated superiority over placebo for generalized anxiety disorder but carries high sedation risk 3
Critical Safety Considerations (Apply to Both Formulations)
Sedation and impairment risks:
- Significant sedative effects impair driving ability, work performance, and cognitive function, with drivers in fatal accidents being 1.5 times more likely to be taking first-generation antihistamines 1
- Hydroxyzine causes 80% sedation rates compared to 50% with diphenhydramine 4
- Performance impairment can occur without subjective awareness of drowsiness 1
Special population warnings:
- Elderly patients: Start at lower doses due to increased risk of falls, fractures, and anticholinergic effects; hydroxyzine should be deprescribed in older adults due to fall risk 4
- Renal impairment: Dose should be halved in moderate renal impairment and avoided in severe renal impairment 1
- Pregnancy: Contraindicated during early pregnancy 1
- Hepatic disease: Avoid in severe liver disease due to inappropriate sedating effects 4
Common Clinical Pitfall
The most important distinction is not between hydroxyzine pamoate and Atarax (which are simply different salt formulations), but rather recognizing that both are first-generation antihistamines with substantial sedative and anticholinergic effects that make them inappropriate for many patients, particularly the elderly and those requiring daytime alertness 2, 1, 4.