Atarax vs Vistaril for PRN Anxiety: No Clinical Difference
Atarax and Vistaril are simply different brand names and salt formulations of the same active drug (hydroxyzine), and there is no clinically meaningful difference between them for PRN anxiety management—however, neither should be used as first-line treatment for anxiety disorders. 1, 2
The Reality: Same Drug, Different Salts
Atarax contains hydroxyzine hydrochloride, while Vistaril contains hydroxyzine pamoate—both convert to the same active compound (hydroxyzine) in the body and have equivalent anxiolytic effects. The salt formulation difference is pharmacologically irrelevant for clinical outcomes. 3, 4
Any perceived differences between these formulations are not supported by evidence and likely reflect marketing distinctions rather than therapeutic ones. 3
Why Hydroxyzine Is NOT Recommended for Anxiety
Current guidelines do not recommend hydroxyzine as first-line treatment for anxiety disorders, despite its historical use. 1, 2
Evidence Against Hydroxyzine:
A 2010 Cochrane systematic review concluded that hydroxyzine cannot be recommended as a reliable first-line treatment in generalized anxiety disorder due to high risk of bias in studies, small sample sizes, and limited evidence quality. 3
The most recent guidelines (2025) from major psychiatric organizations recommend SSRIs (escitalopram, sertraline) or SNRIs (duloxetine, venlafaxine) as first-line pharmacological treatments for anxiety disorders, with no mention of hydroxyzine. 1, 2
Limited Supporting Evidence:
Older studies from the 1990s showed hydroxyzine 50 mg/day was superior to placebo for generalized anxiety disorder, with effects beginning in the first week. 4, 5
However, the primary side effect is sedation/drowsiness (28% vs 14% with placebo), which limits its utility for daytime anxiety management. 5
What You Should Use Instead for PRN Anxiety
For acute anxiety management, the evidence-based approach prioritizes:
First-Line Pharmacological Options:
Start with sertraline 25-50 mg daily or escitalopram 5-10 mg daily as standing (not PRN) treatment, as SSRIs are the gold-standard first-line agents with the best evidence for efficacy and safety. 1, 2
Titrate sertraline by 25-50 mg increments every 1-2 weeks (target 50-200 mg/day) or escitalopram by 5-10 mg increments (target 10-20 mg/day). 1
Expect statistically significant improvement by week 2, clinically significant improvement by week 6, and maximal benefit by week 12. 1
Non-Pharmacological First-Line:
- Cognitive behavioral therapy (CBT) should be combined with medication for optimal outcomes, with individual CBT showing large effect sizes (Hedges g = 1.01) for generalized anxiety disorder. 1
Critical Pitfall to Avoid:
- Benzodiazepines should not be used as first-line monotherapy due to dependence risk, and hydroxyzine's sedating properties make it poorly suited for PRN daytime use. 2, 5
When Hydroxyzine Might Be Considered
If you must use hydroxyzine (despite lack of guideline support), the evidence suggests:
Hydroxyzine 50 mg/day (not PRN dosing) showed efficacy in older trials, but expect significant daytime sedation that typically diminishes after the first week. 4, 5
It may have a role in benzodiazepine withdrawal support (25-50 mg during taper), but this is not its primary indication. 6
There is no evidence supporting true "PRN" (as-needed) dosing of hydroxyzine for anxiety—the studies used daily standing doses. 3, 4, 5