Is Atarax (hydroxyzine) less potent than Vistaril (hydroxyzine pamoate) for treating anxiety and insomnia?

Atarax and Vistaril Are the Same Medication

Atarax and Vistaril are not different in potency—they are simply different brand names and salt formulations of the same active drug, hydroxyzine, and should be considered therapeutically equivalent for treating anxiety and insomnia. 1

Understanding the Formulations

• Atarax contains hydroxyzine hydrochloride, while Vistaril contains hydroxyzine pamoate—these are different salt forms of the identical active ingredient (hydroxyzine) 2
• Both formulations deliver the same antihistamine with anxiolytic properties and produce equivalent clinical effects when dosed appropriately 1, 3
• The different salt forms affect absorption rates and dosing equivalence, but not the fundamental potency of the active drug itself 1

Clinical Efficacy Evidence

• Hydroxyzine (regardless of salt form) demonstrates statistically significant superiority over placebo for generalized anxiety disorder, with anxiolytic effects beginning within the first week of treatment at 50 mg/day 3, 4
• In controlled trials, hydroxyzine showed equivalent efficacy to benzodiazepines (lorazepam, bromazepam, chlordiazepoxide) and buspirone for anxiety treatment, with comparable acceptability and tolerability 1, 5
• The medication maintains efficacy throughout 12 weeks of treatment without development of tolerance, and can be discontinued abruptly without rebound anxiety or withdrawal symptoms 3, 5

Practical Prescribing Considerations

• The standard effective dose is hydroxyzine 50 mg/day for generalized anxiety disorder, regardless of which salt formulation is used 3, 4, 5
• The most common side effect is transient drowsiness (28% vs 14% with placebo), which typically appears during the first week and progressively diminishes with continued treatment 3
• Hydroxyzine has alpha-adrenergic antagonism activity, which can increase the risk of priapism when combined with antipsychotics like risperidone 2

Important Limitations

• Despite efficacy over placebo, hydroxyzine cannot be recommended as a reliable first-line treatment for GAD due to high risk of bias in available studies, small sample sizes, and lack of comparison to modern first-line agents (SSRIs) 1
• Current guidelines do not include hydroxyzine as a first-line option for chronic insomnia or anxiety disorders, with SSRIs (particularly sertraline) and cognitive behavioral therapy being preferred 6, 7