Atomoxetine Starting Dose for ADHD
The recommended starting dose of atomoxetine for ADHD is 40 mg orally once daily, with subsequent titration every 7-14 days to 60 mg then 80 mg daily, up to a maximum of 1.4 mg/kg/day or 100 mg/day (whichever is lower). 1
Weight-Based Dosing Approach
The most current guideline evidence provides a clear sequential dosing strategy 1:
- Initial dose: 40 mg orally once daily
- Titration schedule: Adjust every 7-14 days
- Target progression: 40 mg → 60 mg → 80 mg daily
- Maximum dose: The lesser of 1.4 mg/kg/day or 100 mg/day
Alternative Dosing Framework
An alternative weight-based approach exists, particularly for children and adolescents 1, 2:
- Target dose: 1.2 mg/kg/day appears to be as effective as higher doses 3
- Maximum recommended: 1.4 mg/kg/day or 100 mg/day, whichever is lower 1
- Research demonstrates that 1.2 mg/kg/day and 1.8 mg/kg/day show similar efficacy, with 1.2 mg/kg/day being the appropriate initial target for most patients 3
Adult-Specific Dosing
For adults with ADHD, clinical trials have used fixed-dose regimens 4, 5:
- Studied doses: 60 mg, 90 mg, or 120 mg daily
- These doses demonstrated superior efficacy compared to placebo in well-controlled trials 4, 5
- Atomoxetine can be administered once daily or split into two evenly divided doses 4, 5
Critical Safety Monitoring
All children and adolescents starting atomoxetine must be monitored closely for suicidal ideation, clinical worsening, and unusual behavioral changes, especially during the first few months of treatment or at dose changes. 1
Additional monitoring considerations 1:
- Preexisting cardiovascular disease or cardiac abnormalities require careful assessment
- Watch for emergent psychotic or manic symptoms
- Monitor for aggressive behavior or hostility
- Assess growth parameters during long-term treatment
Common Adverse Effects
The most frequently reported adverse effects in pediatric trials include 1:
- Nausea and vomiting
- Fatigue and somnolence
- Decreased appetite
- Abdominal pain
In adults, additional common effects include dry mouth, insomnia, constipation, dizziness, sweating, and sexual problems 4, 5
Important Pharmacokinetic Consideration
Approximately 7% of the population are poor metabolizers of atomoxetine via CYP2D6, resulting in significantly higher plasma levels and longer half-lives, which may increase adverse effects. 1
- Concomitant use with selective serotonin reuptake inhibitors can elevate serum atomoxetine levels 1
- Dose adjustments may be necessary in poor metabolizers
Maintenance Dosing Evidence
For patients who achieve robust response, maintenance treatment can potentially use lower doses 6:
- Patients maintained on 0.5 mg/kg/day showed similar relapse rates compared to those continuing 1.2-1.8 mg/kg/day 6
- This suggests dose reduction may be feasible after initial response, though this should be individualized based on symptom control