What is the recommended starting dose for atomoxetine (Strattera)?

Starting Dose for Atomoxetine

For children and adolescents up to 70 kg, start atomoxetine at 0.5 mg/kg/day and increase after a minimum of 3 days to a target dose of 1.2 mg/kg/day; for patients over 70 kg and adults, start at 40 mg/day and increase after a minimum of 3 days to a target dose of 80 mg/day. 1

Weight-Based Dosing for Pediatric Patients ≤70 kg

• Initial dose: 0.5 mg/kg/day administered either as a single morning dose or divided into morning and late afternoon/early evening doses 1
• Target dose: 1.2 mg/kg/day reached after a minimum of 3 days at the starting dose 1
• Maximum daily dose should not exceed 1.4 mg/kg or 100 mg, whichever is less 1
• The 1.2 mg/kg/day dose has demonstrated 34-38% reduction in ADHD symptoms versus 13-15.7% with placebo 2

Dosing for Patients >70 kg and Adults

• Initial dose: 40 mg/day administered as a single morning dose or divided doses 1
• Target dose: 80 mg/day reached after a minimum of 3 days at the starting dose 1
• After 2-4 additional weeks, may increase to maximum of 100 mg/day if optimal response not achieved 1
• The maximum recommended total daily dose is 100 mg 1

Critical Titration Principles

• Maintain the initial dose for at least 1-2 weeks before increasing to assess tolerability 2
• Increase doses in small increments (typically 10-25 mg) no more frequently than every 1-2 weeks 2
• Slow titration is better tolerated and helps avoid exceeding the optimal dose 2
• Atomoxetine requires 6-12 weeks to achieve full therapeutic effect, unlike stimulants which work within hours—set appropriate patient expectations 2

Special Population Dosing Adjustments

Hepatic Impairment

• Moderate hepatic insufficiency (Child-Pugh Class B): Reduce initial and target doses to 50% of normal 1
• Severe hepatic insufficiency (Child-Pugh Class C): Reduce initial and target doses to 25% of normal 1

CYP2D6 Poor Metabolizers or Strong CYP2D6 Inhibitor Use

• For patients ≤70 kg: Start at 0.5 mg/kg/day and only increase to 1.2 mg/kg/day if symptoms fail to improve after 4 weeks and initial dose is well tolerated 1
• For patients >70 kg and adults: Start at 40 mg/day and only increase to 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 1

Common Pitfalls to Avoid

• Rapid dose escalation can cause behavioral activation/agitation, including motor restlessness, insomnia, impulsiveness, and aggression 2
• Younger patients are more susceptible to behavioral activation with rapid dose increases 2
• Do not exceed 1.2 mg/kg/day in children without clear clinical justification, as no additional benefit has been demonstrated at higher doses 1
• If side effects occur, return to the previous well-tolerated dose 2

Safety Monitoring Requirements

• Monitor closely for suicidality, clinical worsening, and unusual behavior changes, especially during the first few months or at dose changes 2
• Check blood pressure at baseline and regularly during titration, as atomoxetine can increase blood pressure 3
• Common adverse effects include nausea, vomiting, fatigue, decreased appetite, abdominal pain, and somnolence 2

Administration Considerations

• May be taken with or without food 1
• Can be discontinued without tapering 1
• Capsules should be taken whole and not opened 1