Can a 15-year-old adolescent take mirtazapine (an antidepressant) for sleep issues?

Mirtazapine Use in a 15-Year-Old for Sleep

Mirtazapine can be used in a 15-year-old for sleep issues, but it should be reserved as a third-line option after melatonin and trazodone, with careful monitoring for suicidal ideation during the first few months of treatment. 1, 2

Critical Safety Warning

• The FDA mandates a black box warning that mirtazapine increases the risk of suicidal thoughts or actions in children and young adults under 24 years of age, especially within the first few months of treatment or when the dose is changed. 2
• Close monitoring is essential—watch for new or sudden changes in mood, behavior, thoughts, or feelings, and maintain frequent follow-up visits during the initial treatment period. 2
• Mirtazapine is not FDA-approved for use in children, though it is used off-label in adolescents. 2

Treatment Hierarchy for Adolescent Insomnia

• Melatonin should be the first-line pharmacologic treatment for sleep disturbances in adolescents, as it is the most popular first-choice treatment among pediatric psychiatrists. 3
• Trazodone is the preferred second-line option, with 57% of pediatric psychiatrists reporting it as their second-choice treatment for sleep disturbances. 3
• Mirtazapine ranks as a third-line option after melatonin and trazodone in the pediatric population. 3, 1

When Mirtazapine May Be Appropriate

• Consider mirtazapine when the adolescent has comorbid depression or anxiety along with insomnia, as it can address multiple symptoms simultaneously. 1, 4
• Mirtazapine may be appropriate when first-line agents (melatonin) and second-line agents (trazodone) have failed or are not tolerated. 1
• In children with neurodevelopmental disorders (such as autism spectrum disorders or Angelman syndrome), mirtazapine has shown effectiveness for sleep disorders. 1, 5

Dosing and Administration

• Start with 7.5 mg at bedtime, which is the recommended starting dose for insomnia in adolescents. 1, 4
• The dose can be titrated to 15-30 mg at bedtime if needed, though lower doses (7.5 mg) may be more sedating due to mirtazapine's unique pharmacology. 1, 4
• The mean daily dose used in adolescents with major depression was 32.9 mg, though sleep benefits occur at lower doses. 6

Evidence in Adolescents

• An open-label study of 23 adolescents (ages 12-18) with major depression showed that mirtazapine had a beneficial effect on sleep with rapid onset of action. 6
• Mirtazapine significantly improved sleep onset, reduced nocturnal awakenings, and increased total sleep time in pediatric patients with neurodevelopmental disorders. 5
• In healthy adults, 7.5 mg mirtazapine increased total sleep time by 30 minutes and reduced awakenings by 35-40% compared to placebo. 7

Important Side Effects and Monitoring

• The most common side effects are tiredness, increased appetite, weight gain, and dizziness. 6, 5
• Hyperphagia and weight gain are particularly significant in pediatric patients and led to discontinuation in some cases. 5
• Daytime sleepiness and reduced sustained attention can occur the following day, which may impact school performance. 7
• One pediatric case report documented severe periodic limb movements in a 9-year-old taking mirtazapine, which resolved after discontinuation. 8

Clinical Algorithm

• First, confirm chronic insomnia diagnosis and rule out primary sleep disorders (sleep apnea, restless legs syndrome) through thorough sleep history, sleep diaries, and consideration of actigraphy. 3, 1
• Initiate behavioral therapy and sleep hygiene measures, though sleep hygiene alone is insufficient for chronic insomnia. 3, 1
• Start with melatonin (including extended-release formulations) as first-line pharmacologic treatment. 3
• If melatonin fails, try trazodone as the second-line option. 3
• Consider mirtazapine as third-line if the patient has comorbid depression/anxiety, or if first and second-line agents have failed. 1
• Monitor closely for suicidal ideation every 1-2 weeks during the first 2 months, then monthly thereafter. 2
• Assess for side effects including weight gain, daytime sedation, and movement disorders at each follow-up. 5, 7, 8

Critical Contraindications

• Do not use mirtazapine if the patient is taking an MAOI or has stopped an MAOI within the last 14 days. 2
• Do not start an MAOI for at least 14 days after stopping mirtazapine. 2
• Avoid in patients with known hypersensitivity to mirtazapine. 2