Starting Dose for Strattera (Atomoxetine)
The starting dose of Strattera (atomoxetine) is 40 mg once daily for adults and children over 70 kg, and 0.5 mg/kg/day for children and adolescents up to 70 kg. 1
Dosing Guidelines Based on Weight
For children and adolescents up to 70 kg:
- Initial dose: 0.5 mg/kg/day
- Titration: After a minimum of 3 days, increase to target dose of approximately 1.2 mg/kg/day
- Administration: Can be given as a single daily dose in the morning or divided into two doses (morning and late afternoon/early evening)
- Maximum dose: Should not exceed 1.4 mg/kg/day or 100 mg, whichever is less
For adults and children over 70 kg:
- Initial dose: 40 mg once daily
- Titration: After a minimum of 3 days, increase to target dose of approximately 80 mg/day
- Administration: Can be given as a single daily dose in the morning or divided into two doses
- After 2-4 additional weeks, may increase to maximum of 100 mg if optimal response not achieved
- Maximum recommended dose: 100 mg/day
Important Clinical Considerations
- Atomoxetine capsules should be taken whole, not opened 1
- Can be taken with or without food 1
- No tapering is required when discontinuing 1
- Screen for bipolar disorder before initiating treatment 1
Special Populations
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 1
CYP2D6 Poor Metabolizers or Patients Taking CYP2D6 Inhibitors
- Children ≤70 kg: Start at 0.5 mg/kg/day, only increase to 1.2 mg/kg/day if needed after 4 weeks
- Adults and children >70 kg: Start at 40 mg/day, only increase to 80 mg/day if needed after 4 weeks 1
Efficacy and Dose Response
Research has demonstrated a graded dose-response relationship with atomoxetine. The 1.2 mg/kg/day dose appears to be as effective as higher doses (1.8 mg/kg/day) for most patients 2. Studies suggest that maintaining the target dose for an adequate duration (4-6 weeks) is important for optimal efficacy 3.
Common Pitfalls to Avoid
Underdosing: Real-world data show that adults are often prescribed an average dose of approximately 60 mg/day despite the recommended 80 mg/day target dose 3. This suboptimal dosing may lead to poor treatment outcomes.
Inadequate trial duration: Atomoxetine may require 4-6 weeks at the target dose to demonstrate full efficacy, unlike stimulants which show more immediate effects.
Failure to adjust for special populations: Patients with hepatic impairment or those taking CYP2D6 inhibitors require dose adjustments to prevent adverse effects.
Inappropriate discontinuation: Atomoxetine can be discontinued without tapering, unlike some other psychiatric medications 1.
For maintenance treatment, some evidence suggests that a lower dose (0.5 mg/kg/day) may be effective for maintaining response in patients who have achieved symptom control on higher doses, which could reduce long-term side effects 4.
AI: I noticed I need to make a correction. The FDA label clearly states that atomoxetine should be initiated at 40 mg daily for adults and children over 70 kg, and at 0.5 mg/kg/day for children and adolescents up to 70 kg.