What is the recommended dosage for Strattera (Atomoxetine)?

Strattera (Atomoxetine) Dosing

Start atomoxetine at 0.5 mg/kg/day for children/adolescents under 70 kg or 40 mg/day for those over 70 kg and adults, increase after a minimum of 3 days to a target dose of 1.2 mg/kg/day (up to 80 mg/day for those over 70 kg), with a maximum of 1.4 mg/kg/day or 100 mg/day, whichever is less. 1

Initial Dosing by Weight

Children and Adolescents Under 70 kg

• Starting dose: 0.5 mg/kg/day (total daily dose) 1
• Target dose: 1.2 mg/kg/day after minimum 3 days 1
• Maximum dose: 1.4 mg/kg/day or 100 mg/day, whichever is less 1
• Single doses should not exceed 15 mg in children under 25 kg 2

Children/Adolescents Over 70 kg and Adults

• Starting dose: 40 mg/day 1
• Target dose: 80 mg/day after minimum 3 days 1
• Maximum dose: 100 mg/day after 2-4 additional weeks if optimal response not achieved 1

Titration Schedule

Increase doses gradually at 1-2 week intervals to avoid behavioral activation and gastrointestinal side effects. 3, 2

• Maintain initial dose for at least 1-2 weeks before increasing 3
• Increase by small increments (typically 10-25 mg) no more frequently than every 1-2 weeks 3
• The typical titration pattern for adolescents over 70 kg and adults: 40 mg → 60 mg → 80 mg/day, adjusted every 7-14 days 2

Critical Pitfall: Rapid Dose Escalation

Avoid increasing doses too quickly, as this causes behavioral activation (agitation, restlessness, insomnia, impulsiveness, aggression), particularly in younger patients. 3 Initial somnolence and gastrointestinal symptoms also occur when doses are increased too rapidly 2.

Administration Details

• Can be given once daily in the morning OR split into two evenly divided doses (morning and late afternoon/early evening) 1
• May be taken with or without food 1
• Capsules must be swallowed whole, not opened 1
• Can be discontinued without tapering 1

Special Population Dosing Adjustments

Hepatic Impairment

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

CYP2D6 Poor Metabolizers or Strong CYP2D6 Inhibitor Use

When using strong CYP2D6 inhibitors (paroxetine, fluoxetine, quinidine) or in known CYP2D6 poor metabolizers:

Children/adolescents under 70 kg:

• Start at 0.5 mg/kg/day 1
• 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

Children/adolescents over 70 kg and adults:

• Start at 40 mg/day 1
• Only increase to usual target of 80 mg/day if symptoms fail to improve after 4 weeks AND initial dose is well tolerated 1

Timeline to Full Effect

Set expectations that atomoxetine requires 6-12 weeks to achieve full therapeutic effect, unlike stimulants which work within hours. 3 This delayed response timeline is critical for patient adherence and realistic expectations.

Pre-Treatment Requirements

Before initiating atomoxetine:

• Screen for personal or family history of bipolar disorder, mania, or hypomania 1
• Obtain baseline blood pressure, pulse, height, and weight 2
• Document prior ADHD treatments, including medications, dosages, duration, response, and side effects 2

Safety Monitoring

• Monitor closely for suicidality, clinical worsening, and unusual behavioral changes, especially during the first few months or at dose changes 3
• Common adverse effects include nausea, vomiting, fatigue, decreased appetite, abdominal pain, and somnolence 3
• If side effects occur, consider returning to the previous well-tolerated dose 3

Efficacy Data

The target dose of 1.2 mg/kg/day reduces ADHD symptoms by 34-38% versus 13-15.7% with placebo in children with ADHD 3. No additional benefit has been demonstrated for doses higher than 1.2 mg/kg/day 1.