Maximum Recommended Dosage of Atomoxetine (Strattera)
The maximum recommended dosage of atomoxetine is 1.4 mg/kg/day or 100 mg/day, whichever is lower. 1, 2
Dosing Guidelines Based on Weight
For Children and Adolescents up to 70 kg:
- Initial dose: 0.5 mg/kg/day
- Target dose: 1.2 mg/kg/day (after minimum of 3 days)
- Maximum dose: 1.4 mg/kg/day or 100 mg/day, whichever is lower
- Administration: Either as a single daily dose in the morning or divided into morning and late afternoon/evening doses
For Children and Adolescents over 70 kg and Adults:
- Initial dose: 40 mg/day
- Target dose: 80 mg/day (after minimum of 3 days)
- Maximum dose: 100 mg/day
- Administration: Either as a single daily dose in the morning or divided into morning and late afternoon/evening doses
Clinical Evidence Supporting Dosing Recommendations
Research has demonstrated a graded dose-response relationship with atomoxetine, with 1.2 mg/kg/day showing similar efficacy to 1.8 mg/kg/day in clinical trials 3. This suggests that 1.2 mg/kg/day is likely the appropriate initial target dose for most patients, with the maximum ceiling of 1.4 mg/kg/day or 100 mg providing an upper limit for safety and tolerability.
Special Dosing Considerations
Hepatic Impairment
- Moderate hepatic impairment (Child-Pugh Class B): Reduce initial and target doses to 50% of normal dose
- Severe hepatic impairment (Child-Pugh Class C): Reduce initial and target doses to 25% of normal dose 2
CYP2D6 Poor Metabolizers or Patients Taking CYP2D6 Inhibitors
- Children and adolescents up to 70 kg: Start at 0.5 mg/kg/day and only increase to 1.2 mg/kg/day if needed after 4 weeks
- Children and adolescents over 70 kg and adults: Start at 40 mg/day and only increase to 80 mg/day if needed after 4 weeks 2
Safety Considerations
- The safety of single doses over 120 mg and total daily doses above 150 mg has not been systematically evaluated 2
- Discontinuation rates appear to be dose-dependent, with higher rates at dosages greater than 1.5 mg/kg/day 4
- Atomoxetine does not require tapering when discontinuing 2
Maintenance Treatment
For long-term maintenance therapy, some evidence suggests that lower doses (0.5 mg/kg/day) may be effective in maintaining symptom control in patients who have had a robust initial response to higher doses 5. This approach could reduce drug exposure and potential tolerability issues during chronic treatment.
Important Clinical Considerations
- Atomoxetine can be taken with or without food 2
- Capsules should be taken whole, not opened 2
- Effects may not be observed until several weeks after initiation of treatment (6-12 weeks) 1
- Regular monitoring for suicidal ideation, clinical worsening, and unusual changes in behavior is recommended, especially during the first few months of treatment or at times of dose changes 1
By following these dosing guidelines and considering individual patient factors, clinicians can optimize the safety and efficacy of atomoxetine treatment for ADHD.