Atomoxetine (Strattera) Dosing Schedule
The recommended dose increasing schedule for atomoxetine (Strattera) begins with an initial dose of 0.5 mg/kg/day for children and adolescents up to 70 kg or 40 mg daily for adults and children over 70 kg, with increases after a minimum of 3 days to a target dose of 1.2 mg/kg/day or 80 mg daily, respectively. 1, 2
Initial Dosing
Children and Adolescents ≤70 kg:
- Starting dose: 0.5 mg/kg/day
- Administration: Either as a single morning dose or divided into morning and late afternoon doses
- Maximum dose: Should not exceed 1.4 mg/kg/day or 100 mg daily (whichever is less)
Adults and Children >70 kg:
- Starting dose: 40 mg once daily
- Administration: Either as a single morning dose or divided into morning and late afternoon doses
- Target dose: 80 mg daily
- Maximum dose: 100 mg daily
Titration Schedule
The FDA label specifies that dose increases should occur after a minimum of 3 days 1. However, clinical practice suggests a more gradual approach:
- Increase dose after 7-14 days if tolerated 2
- For adults, typical progression: 40 mg → 60 mg → 80 mg 2
- After 2-4 additional weeks at 80 mg, may increase to maximum of 100 mg if optimal response not achieved 1
Special Populations
Hepatic Impairment:
- Moderate impairment (Child-Pugh Class B): Reduce initial and target doses to 50% of normal dose
- Severe impairment (Child-Pugh Class C): Reduce initial and target doses to 25% of normal dose 1, 3
Poor CYP2D6 Metabolizers or Patients Taking Strong CYP2D6 Inhibitors:
- Children ≤70 kg: Start at 0.5 mg/kg/day and only increase to 1.2 mg/kg/day if symptoms don't improve after 4 weeks
- Adults and children >70 kg: Start at 40 mg/day and only increase to 80 mg/day if symptoms don't improve after 4 weeks 1
Administration Considerations
- May be taken with or without food
- Capsules should be taken whole, not opened
- No tapering required when discontinuing 1
Monitoring During Titration
- Weekly contact during initial dose titration is recommended 4
- Monitor for common side effects: gastrointestinal symptoms (24.1%), aggression (12.8%), and increased hyperactivity (9%) 5
- Blood pressure and pulse should be checked regularly 4
Duration of Treatment
- An adequate trial requires at least 4 weeks at the target dose before judging efficacy 6
- Some patients may require 4-6 weeks at the target dose to see full benefits 6
Common Pitfalls
- Underdosing: Real-world data shows adults often receive ~60 mg/day instead of the recommended 80 mg/day target dose 6
- Premature efficacy assessment: Judging efficacy before 4-6 weeks at target dose may lead to unnecessary discontinuation
- Inadequate duration of titration: Rushing the titration process can increase side effects and reduce tolerability
- Failure to adjust for special populations: Not accounting for hepatic impairment or CYP2D6 status can lead to adverse effects
Atomoxetine is particularly useful for patients at risk of substance abuse or those with comorbid anxiety or tics 7. When properly dosed according to this schedule, it has demonstrated significant improvement in ADHD symptoms over placebo at both 12 and 24 weeks 8.