Can Mirtazapine (Remeron) Be Prescribed for Pediatric Clients?
Mirtazapine is not FDA-approved for use in pediatric patients with major depressive disorder, and the FDA label explicitly states that safety and effectiveness have not been established in this population. 1
FDA Regulatory Status and Black Box Warning
The FDA has not approved mirtazapine for any indication in pediatric patients, as two placebo-controlled trials in 258 pediatric patients with MDD showed insufficient data to establish safety and effectiveness. 1
Antidepressants, including mirtazapine, carry a black box warning for increased risk of suicidal thoughts and behaviors in pediatric patients. 1
The only FDA-approved antidepressant for pediatric depression is fluoxetine, which has demonstrated superior efficacy to other agents in this population. 2
Limited Evidence for Off-Label Use
While mirtazapine lacks FDA approval for pediatric use, there is limited research evidence suggesting potential efficacy in specific contexts:
Depression Studies
An open-label pilot study of 23 adolescents (ages 12-18) with major depression showed marked efficacy on depression rating scales with doses of 30-45 mg daily, though this was uncontrolled and lacked a placebo comparison. 3
A multiple-treatments meta-analysis found that mirtazapine exhibited high efficacy and optimal safety balance compared to other antidepressants in pediatric MDD, though the evidence base was limited. 2
Anxiety Disorders
- In an 8-week open-label trial of children and adolescents (ages 8-17) with social phobia, only 56% responded to treatment and 22% discontinued due to adverse effects including fatigue and irritability. 4
Autism Spectrum Disorder
- A small study (25 children ages 2-20 years) with ASD showed mirtazapine improved sleep disorders and behavioral symptoms at doses of 7.5-45 mg daily, though this was for insomnia rather than depression. 5
Critical Safety Concerns in Pediatric Populations
Weight gain is a particularly severe problem in pediatric patients treated with mirtazapine:
In an 8-week pediatric clinical trial, 49% of mirtazapine-treated patients gained at least 7% of body weight, compared to only 5.7% of placebo-treated patients. 1
The mean weight increase was 4 kg for mirtazapine versus 1 kg for placebo. 1
Significant weight gain was also observed in the social phobia trial, contributing to treatment discontinuation. 4
Other common adverse effects in pediatric patients include:
- Somnolence (sedation), which occurred in 54% of adult patients and led to discontinuation in 10.4%. 1
- Increased appetite (17% in adults). 1
- Fatigue and irritability, which led to discontinuation in 22% of pediatric social phobia patients. 4
Comparison to Preferred Pediatric Antidepressants
When antidepressant treatment is necessary in pediatric patients, evidence-based alternatives should be prioritized:
Combined fluoxetine plus cognitive behavioral therapy (CBT) exhibited the highest efficacy in pediatric MDD, with fluoxetine alone superior to other SSRIs and SNRIs. 2
Sertraline and escitalopram demonstrated superior acceptability (lower dropout rates) compared to fluoxetine. 2
For anxiety disorders specifically, duloxetine is the only SNRI with FDA approval for pediatric anxiety disorders. 6
Clinical Recommendation
Mirtazapine should not be used as a first-line, second-line, or even third-line antidepressant in pediatric patients with depression. The lack of FDA approval, insufficient efficacy data, black box warning for suicidality, and particularly concerning weight gain profile (49% gaining ≥7% body weight) make it inappropriate for routine pediatric use. 1, 2
If antidepressant treatment is indicated in a pediatric patient:
First-line: Fluoxetine (with or without CBT), as it has the strongest evidence base and FDA approval for pediatric MDD. 2
Second-line: Sertraline or escitalopram, which have better tolerability profiles than fluoxetine. 2
Mirtazapine might only be considered in highly treatment-resistant cases where multiple FDA-approved options have failed, and only after consultation with a child psychiatry specialist, with careful monitoring for weight gain and suicidality. 1, 3
Special Circumstances Where Mirtazapine Has Been Used
The only pediatric context where mirtazapine has shown consistent benefit is insomnia in children with autism spectrum disorder, where it improved sleep disorders in 16 of 17 children at doses of 7.5-45 mg daily. 5 However, even this use remains off-label and should be reserved for cases where behavioral interventions and melatonin have failed.