Hydroxyzine PRN Dosing Schedule for Anxiety or Sedation in Adults
For anxiety in adults, hydroxyzine should be administered at 50 to 100 mg four times daily (q.i.d.) as needed. 1
Dosing Recommendations for Anxiety
- The FDA-approved dosing for hydroxyzine in anxiety and tension associated with psychoneurosis is 50 to 100 mg four times daily (q.i.d.) for adults 1
- For sedation when used as a premedication, the recommended dose is 50 to 100 mg for adults 1
- Dosing should be adjusted according to the patient's response to therapy 1
Timing Considerations
- When used for anxiety, the standard four-times-daily dosing is recommended for optimal therapeutic effect 1
- For minimizing daytime sedation while maintaining efficacy, evening dosing (bedtime administration) can help mitigate side effects while maintaining H1-receptor antagonism the following morning 2
- Bedtime dosing of hydroxyzine (50 mg qhs) has been shown to reduce reaction time degradation and adverse subjective symptoms compared to divided doses throughout the day 2
Efficacy Data
- Clinical trials have confirmed hydroxyzine's efficacy at a fixed dose of 50 mg in generalized anxiety disorder, with superiority over placebo from the first week of treatment 3
- Studies show that hydroxyzine can produce a statistically and clinically significant anxiolytic effect starting during the first week of treatment and maintained throughout a 4-week period 4
- Efficacy is maintained even after abrupt discontinuation without rebound anxiety or withdrawal symptoms 4, 3
Side Effect Management
- The most common side effect is transient sleepiness (28% vs 14% with placebo), which typically appears during the first week and progressively diminishes with continued treatment 4
- Other common side effects include dry mouth (14% vs 5% with placebo), weight gain (12% vs 10%), and loss of concentration (9% vs 8%) 4
- When used as a sedative for anxiety, the sedating properties can be beneficial, particularly for patients experiencing anxiety-related sleep disturbances 1, 5
Special Considerations
- For elderly patients or those with hepatic impairment, consider starting at the lower end of the dosing range (50 mg) due to potential for increased sensitivity to side effects 1
- Hydroxyzine may also be used for pruritus management at a lower dose of 25 mg three or four times daily (t.i.d. or q.i.d.) 1
- Avoid combining with other sedating medications when possible, as this may increase the risk of excessive sedation 6
Monitoring
- Monitor for excessive sedation, especially when initiating therapy or when combined with other central nervous system depressants 6
- Assess for paradoxical agitation, which can occur with antihistamines, particularly in elderly patients 6
- Evaluate the ongoing need for medication regularly, as some patients develop tolerance to the sedative effects while maintaining anxiolytic benefits 4