Hydroxyzine HCl is Preferred Over Hydroxyzine Pamoate for Anxiety
For anxiety treatment, hydroxyzine hydrochloride (HCl) is preferred over hydroxyzine pamoate due to its faster onset of action and more reliable absorption profile. While both formulations contain the same active ingredient, the HCl salt form has pharmacokinetic advantages that make it more suitable for the acute management of anxiety symptoms.
Comparison of Hydroxyzine Formulations
Hydroxyzine HCl
- Faster onset of action (important for anxiety symptoms)
- More consistent absorption profile
- Better suited for as-needed anxiety management
- Available as Atarax® (brand name)
Hydroxyzine Pamoate
- Slower release formulation
- More commonly used for allergic conditions
- Available as Vistaril® (brand name)
- May have slightly longer duration of action
Clinical Evidence and Recommendations
Hydroxyzine has demonstrated efficacy as an anxiolytic in several clinical trials. A Cochrane review found hydroxyzine to be more effective than placebo for generalized anxiety disorder (GAD) 1. Another study showed that hydroxyzine at 50 mg/day produces a statistically significant anxiolytic effect beginning in the first week of treatment 2.
When treating anxiety symptoms, the British Journal of Dermatology guidelines note that hydroxyzine can be effective, particularly when added at night to help patients sleep better 3. The faster absorption profile of the HCl formulation makes it particularly suitable for this purpose.
Dosing Considerations
- Starting dose: 25-50 mg for adults
- Can be taken up to 3-4 times daily as needed
- Maximum daily dose typically 100 mg for anxiety (though up to 400 mg has been used in some settings)
- For elderly patients or those with hepatic impairment, lower doses are recommended
Important Considerations and Precautions
Side Effects
- Sedation/drowsiness (most common side effect)
- Dry mouth
- Blurred vision
- Weight gain
- Potential cognitive impairment
The British Journal of Dermatology guidelines caution that hydroxyzine should be avoided in severe hepatic impairment and used with caution during pregnancy, particularly in the first trimester 3.
Drug Interactions
- Use caution when combining with other CNS depressants
- Avoid concurrent use with drugs that prolong QT interval
- Be cautious when combining with antipsychotics like risperidone, as there is a case report of priapism when hydroxyzine was added to risperidone therapy 4
Alternative Options for Anxiety
If hydroxyzine is not effective or not tolerated, consider:
- SSRIs (first-line for chronic anxiety disorders)
- SNRIs (particularly for anxiety with pain symptoms)
- Buspirone (non-sedating anxiolytic)
- Cognitive behavioral therapy (strong evidence as augmentation strategy) 5
Conclusion
For the treatment of anxiety, hydroxyzine HCl is the preferred formulation over hydroxyzine pamoate due to its faster onset of action and more reliable absorption profile. This makes it more suitable for managing acute anxiety symptoms, particularly when used on an as-needed basis.