Strattera Starting Dose
For children and adolescents weighing up to 70 kg, start Strattera at 0.5 mg/kg/day, and for those over 70 kg and adults, start at 40 mg/day. 1
Weight-Based Dosing Algorithm
Children and Adolescents ≤70 kg
- Initial dose: 0.5 mg/kg/day
- Target dose: 1.2 mg/kg/day (after minimum 3 days)
- Maximum dose: 1.4 mg/kg/day or 100 mg/day, whichever is less 1
The FDA label specifies this sequential approach: begin at 0.5 mg/kg/day, increase after at least 3 days to approximately 1.2 mg/kg/day (the target dose shown effective in clinical trials), and if needed after 2-4 additional weeks, may increase to maximum 1.4 mg/kg/day 1, 2.
Children and Adolescents >70 kg and Adults
- Initial dose: 40 mg/day
- Target dose: 80 mg/day (after minimum 3 days)
- Maximum dose: 100 mg/day 1
Start at 40 mg daily, increase after at least 3 days to the target of 80 mg (given either once daily in the morning or split into morning and late afternoon/evening doses), and if response remains suboptimal after 2-4 additional weeks, may increase to maximum 100 mg/day 1.
Critical Dosing Adjustments
Hepatic Impairment
Moderate hepatic impairment (Child-Pugh Class B): Reduce initial and target doses to 50% of normal dose 1, 3
Severe hepatic impairment (Child-Pugh Class C): Reduce initial and target doses to 25% of normal dose 1, 3
This adjustment is essential because atomoxetine clearance is significantly reduced in hepatic impairment, with systemic exposure nearly doubling in affected patients 3.
CYP2D6 Poor Metabolizers or Strong CYP2D6 Inhibitor Use
For children/adolescents ≤70 kg: Start at 0.5 mg/kg/day and only increase to usual target of 1.2 mg/kg/day if symptoms fail to improve after 4 weeks and initial dose is well tolerated 1
For children/adolescents >70 kg and adults: Start at 40 mg/day and only increase to usual target of 80 mg/day if symptoms fail to improve after 4 weeks and initial dose is well tolerated 1
Strong CYP2D6 inhibitors include paroxetine, fluoxetine, and quinidine. Approximately 7% of the population are poor metabolizers with significantly higher plasma levels and longer half-lives, increasing adverse effect risk 4.
Key Clinical Considerations
Titration speed matters: The most common adverse effects (nausea, vomiting, fatigue, decreased appetite, abdominal pain, somnolence) are particularly problematic if dosage increases too rapidly 5, 4. The minimum 3-day interval between dose increases is designed to minimize gastrointestinal symptoms.
Duration before judging efficacy: Maintain patients at target dose for 4-6 weeks before concluding treatment is ineffective 6. Real-world data show frequent underdosing (average ~60 mg/day in adults versus recommended 80 mg/day target), which may contribute to treatment failure 6.
Administration flexibility: Strattera may be taken with or without food and can be given once daily or split into two doses (morning and late afternoon/evening) 1. Capsules must be swallowed whole and should not be opened 1.
Monitoring requirements: Before initiating atomoxetine, obtain personal and family cardiac history (sudden death, cardiovascular symptoms, Wolff-Parkinson-White syndrome, hypertrophic cardiomyopathy, long QT syndrome). If risk factors present, obtain additional cardiac evaluation including ECG 5. Monitor closely for suicidal ideation, clinical worsening, and unusual behavioral changes, especially during the first few months or at dose changes, as atomoxetine carries an FDA black box warning for increased suicidal ideation risk in children and adolescents 4, 1.
Discontinuation: Atomoxetine can be discontinued without tapering, unlike alpha-2 agonists 1.