What is the recommended dosage and treatment approach for adults taking Strattera (atomoxetine) for Attention Deficit Hyperactivity Disorder (ADHD)?

Atomoxetine (Strattera) Dosage and Treatment Approach for Adults with ADHD

For adults with ADHD, atomoxetine should be initiated at 40 mg once daily and titrated to a target dose of 80-100 mg/day, which can be administered as a single daily dose or split into two evenly divided doses. 1, 2

Dosing Protocol

• Initial dose: 40 mg once daily
• Titration: After a minimum of 3 days, increase to target dose
• Target dose: 80-100 mg/day (mean effective dose: 83 mg/day)
• Administration options:
  • Once-daily dosing (80 mg QD)
  • Twice-daily dosing (40 mg BID)
  • Both regimens are effective, but BID dosing may reduce nausea (16.4% vs 32.4% with QD dosing) 3

Pharmacokinetic Considerations

• Atomoxetine is metabolized primarily through CYP2D6, creating two distinct patient populations 4:

  • CYP2D6 extensive metabolizers:
    • Plasma half-life: 5.2 hours
    • Minimal accumulation with multiple dosing
  • CYP2D6 poor metabolizers:
    • Plasma half-life: 21.6 hours
    • 10-fold higher steady-state plasma concentrations
    • Significant accumulation with multiple dosing

• Despite pharmacokinetic differences, the frequency and severity of adverse events are similar regardless of CYP2D6 phenotype 4

Special Populations

• Patients with renal insufficiency:

  • No dose adjustment needed, even for end-stage renal disease 5
  • Standard dosing regimen can be used

• Patients with comorbid anxiety disorders:

  • Atomoxetine does not worsen anxiety in patients with comorbid anxiety disorders 5
  • Effective dose for adults with ADHD and social anxiety disorder: mean daily dose 83 mg/day 5

Monitoring and Follow-up

• Initial treatment phase: Follow-up every 3-4 weeks 6
• Once stabilized: Follow-up every 3-6 months 6
• Parameters to monitor:
  • Efficacy using standardized rating scales
  • Vital signs (particularly heart rate and blood pressure)
  • Weight and appetite
  • Sleep patterns
  • Mood changes

Adverse Effects Management

Common adverse effects include:

• Dry mouth
• Insomnia
• Nausea (more common with once-daily dosing)
• Decreased appetite
• Constipation
• Dizziness
• Sexual problems

Cardiovascular effects:

• Modest increases in heart rate and blood pressure may occur
• These typically decrease upon cessation of treatment 1, 2
• No QT interval prolongation has been observed 1, 2

Advantages of Atomoxetine

• Non-stimulant medication with no abuse potential 1, 2
• Not a controlled substance, allowing for more convenient prescription processing 1, 2
• Can be administered once daily or split into two doses based on tolerability 1, 2
• Particularly valuable for patients at risk for substance abuse 1, 2

Clinical Pearls

• While lower maintenance doses (0.5 mg/kg/day) have been studied in pediatric populations 7, there is insufficient evidence to recommend this approach in adults
• The subjective effects profile differs from stimulants like methylphenidate 1, 2
• Full therapeutic effect may take several weeks to develop, unlike the immediate effects seen with stimulants