What dose of hydroxyzine should be added to a patient's regimen who is already taking 3 mg of melatonin for sleep difficulties and should melatonin be discontinued?

Hydroxyzine Dosing for Sleep in Adolescents

Add hydroxyzine 25-50 mg at bedtime and continue the melatonin 3 mg, as there is no contraindication to combining these medications and the melatonin dose is already at the recommended starting level for adolescents with psychiatric comorbidities. 1, 2

Hydroxyzine Dosing Strategy

For adolescents (>6 years), the FDA-approved sedative dose is 50-100 mg daily in divided doses, but for bedtime sedation specifically, start with 25-50 mg at bedtime. 3

• Start conservatively at 25 mg at bedtime given this is a psychiatric inpatient with recent suicide attempt 3, 4
• Can increase to 50 mg after 2-3 nights if 25 mg is insufficient and well-tolerated 3
• The lower starting dose minimizes morning sedation while still providing sleep benefit 4

Melatonin Management

Do not discontinue the melatonin 3 mg. 1, 2

• The current 3 mg dose is appropriate for adolescents with psychiatric comorbidities (recommended range 3-5 mg) 1, 2
• Since she weighs likely >40 kg at age 14, the 3 mg dose is at the lower end of the recommended range 1, 2
• Consider increasing melatonin to 5 mg if hydroxyzine alone doesn't fully resolve sleep issues, as this remains within guideline recommendations for adolescents with psychiatric comorbidities 1, 2
• Administer melatonin 1.5-2 hours before desired bedtime for optimal circadian effect 1, 2

Timing and Administration

• Melatonin: 1.5-2 hours before bedtime (e.g., if bedtime is 10 PM, give at 8-8:30 PM) 1, 2
• Hydroxyzine: 30-60 minutes before bedtime (e.g., 9:30 PM for 10 PM bedtime) 3
• This staggered timing allows melatonin to work on circadian rhythm while hydroxyzine provides direct sedative effect 1, 2

Additional Sleep Hygiene Measures

Implement these behavioral interventions alongside medication: 1

• Avoid caffeine after 2:00 PM, as it counteracts melatonin's effects 1
• Eliminate alcohol, which interacts with both medications and psychiatric conditions 1
• Avoid morning/afternoon melatonin dosing, as this worsens circadian misalignment 1
• Ensure consistent sleep-wake schedule, even on weekends 1

Important Safety Considerations

Monitor for these specific concerns: 1, 4

• Morning sedation/hangover effect: More common with higher hydroxyzine doses; if occurs, reduce dose 1, 4
• Vivid dreams or nightmares: Known melatonin side effect that could be distressing in this population; if occurs, consider reducing melatonin dose 5
• Mood changes: Melatonin has been associated with increased depressive symptoms in some individuals; monitor closely given recent suicide attempt 1, 5
• Avoid long-term melatonin use beyond 3-4 months for primary insomnia, though longer use may be appropriate for circadian rhythm disorders 1

Treatment Duration and Reassessment

• Assess response after 1-2 weeks of combined therapy 1
• If sleep improves, continue current regimen 1
• If inadequate response after 2 weeks, increase melatonin to 5 mg (still within recommended range for her age and psychiatric comorbidity) 1, 2
• Periodic attempts to reduce frequency and dose are indicated to determine lowest effective dose 1

Critical Caveat

One case report documented hydroxyzine precipitating acute encephalopathy in a patient with hepatic disease, though this patient had cirrhosis and minimal hepatic encephalopathy—not applicable to your patient but worth noting that hydroxyzine can cause CNS effects. 4 In psychiatrically vulnerable adolescents, start low and monitor closely for any paradoxical agitation or mood changes.