Hydroxyzine Dosing for Adult Anxiety
For adults with anxiety, the FDA-approved dosing of hydroxyzine is 50-100 mg four times daily (QID), though starting at 25-50 mg and titrating based on response is a practical approach in clinical practice. 1
Standard Dosing Regimen
- The FDA label specifies 50-100 mg QID for symptomatic relief of anxiety and tension associated with psychoneurosis. 1
- The onset of action occurs within 15-30 minutes, with effects lasting 4-6 hours, which supports the QID dosing schedule. 2
- Clinical trials demonstrating efficacy in generalized anxiety disorder used 50 mg/day as a single daily dose, showing significant anxiolytic effects beginning in the first week of treatment. 3, 4
Practical Dosing Strategies
- Start with 25 mg three to four times daily (TID or QID) in elderly patients or those sensitive to sedative effects, then titrate upward as needed. 2
- For patients with comorbid anxiety and insomnia, administering a higher dose (50-100 mg) at bedtime provides dual benefits while minimizing daytime sedation. 2
- The anticholinergic effects may provide better control of somatic anxiety symptoms (trembling, tension) compared to non-sedating alternatives. 2
Duration and Efficacy
- Hydroxyzine demonstrated sustained efficacy over 12 weeks in controlled trials, with significant improvement in Hamilton Anxiety Rating Scale scores compared to placebo (mean reduction -12.16 vs -9.64, p=0.019). 4
- Efficacy was comparable to benzodiazepines (bromazepam 6 mg/day) without the risk of dependence or withdrawal symptoms upon abrupt discontinuation. 4
- After 4 weeks of treatment at 50 mg/day, abrupt discontinuation showed no rebound anxiety or withdrawal symptoms. 3
Special Populations and Precautions
- In moderate renal impairment, reduce the dose by 50%; avoid hydroxyzine entirely in severe renal impairment (creatinine clearance <10 mL/min). 5
- Avoid in severe liver disease due to enhanced sedating effects. 5
- Use with extreme caution in elderly patients who are more susceptible to anticholinergic effects (confusion, urinary retention, falls). 2, 5
- Contraindicated in patients with closed-angle glaucoma, prostatic hypertrophy, and cognitive impairment. 2
Common Adverse Effects
- Drowsiness/sleepiness is the most common side effect, occurring in approximately 28% of patients (vs 14% with placebo), but typically diminishes after the first week of treatment. 3
- Other side effects include dry mouth (14%), weight gain (12%), and loss of concentration (9%). 3
- Avoid concomitant use with other CNS depressants as this significantly enhances performance impairment. 5
Clinical Positioning
- Hydroxyzine represents an effective non-benzodiazepine alternative for GAD, particularly useful when benzodiazepine dependence is a concern. 4
- The lack of tolerance development and low addiction potential make it suitable for longer-term anxiety management. 2
- For patients not responding to hydroxyzine monotherapy, consider adding an H2-antagonist (such as cimetidine) for enhanced control. 5