What is the recommended dosing for Strattera (atomoxetine) in adults with Attention Deficit Hyperactivity Disorder (ADHD)?

Strattera (Atomoxetine) Dosing in Adults with ADHD

Start atomoxetine at 40 mg orally once daily, titrate every 7-14 days to 60 mg then 80 mg daily, with a maximum dose of 1.4 mg/kg/day or 100 mg/day, whichever is lower. 1, 2

Initial Dosing Strategy

• Starting dose: 40 mg orally once daily 1, 2
• Titration schedule: Increase dose every 7-14 days 1, 2
• Titration sequence: 40 mg → 60 mg → 80 mg daily 1, 2
• Maximum dose: The lesser of 1.4 mg/kg/day or 100 mg/day 1, 2

Target Dosing and Duration

Real-world data reveal a critical problem: adults are frequently underdosed at approximately 60 mg/day when the recommended target dose is 80 mg/day. 3 Maintain patients at the target dose of 80 mg/day for 4-6 weeks before judging efficacy. 3 This adequate duration at target dose is essential for ADHD symptom improvement. 3

Clinical trials in adults used doses of 60,90, or 120 mg/day, demonstrating superior efficacy compared to placebo across all doses. 4, 5

Once Daily vs. Twice Daily Administration

• Both once-daily and twice-daily dosing are safe, well-tolerated, and efficacious 6
• For 80 mg total daily dose: can give as 80 mg once daily OR 40 mg twice daily 6
• Nausea occurs significantly less frequently with twice-daily dosing (16.4%) compared to once-daily dosing (32.4%) 6
• Twice-daily dosing showed slightly greater symptom reduction in head-to-head comparison 6
• Prescribers have flexibility to adjust dosing strategy based on individual tolerability without safety concerns 6

Critical Safety Monitoring Requirements

Monitor closely for suicidal ideation, clinical worsening, and unusual behavioral changes, especially during the first few months of treatment or at dose changes. 2 While this black box warning applies primarily to children and adolescents, vigilance remains important in adults. 1

Cardiovascular Precautions

• Assess for preexisting cardiovascular disease or cardiac abnormalities before initiating treatment 2
• Monitor blood pressure and heart rate, as modest increases occur but are generally well tolerated 4, 5
• These cardiovascular changes gradually decrease upon treatment cessation 4, 5

Pharmacokinetic Considerations Affecting Dosing

CYP2D6 Poor Metabolizers

• Approximately 7% of the population are CYP2D6 poor metabolizers 2
• These patients have significantly higher plasma levels and longer half-lives 2
• Increased risk of adverse effects in poor metabolizers 1, 2
• Consider lower doses or more gradual titration in known poor metabolizers 1

Drug Interactions

• Selective serotonin reuptake inhibitors (SSRIs) can elevate serum atomoxetine levels 1, 2
• Dose adjustments may be necessary when combining with CYP2D6 inhibitors 2

Renal Insufficiency

• No dose adjustment needed for renal insufficiency, including end-stage renal disease 7
• Exposure increases approximately 65% in end-stage renal disease, but when corrected for mg/kg dose, no difference exists 7

Common Adverse Effects to Anticipate

The most frequently reported adverse effects in adults include: 4, 5

• Dry mouth
• Insomnia
• Nausea (significantly reduced with twice-daily dosing)
• Decreased appetite
• Constipation
• Dizziness
• Sweating
• Dysuria
• Sexual dysfunction (erectile dysfunction, other sexual problems)
• Palpitations

Withdrawal rates due to adverse events in clinical trials ranged from 7.8-9.3% for atomoxetine versus 2.4-4.3% for placebo. 4, 5

Key Advantages in Adult ADHD Treatment

• First ADHD medication approved specifically for adult use based on adult clinical trials 4, 5
• Not a controlled substance—no abuse or diversion potential 4, 5
• Repeat prescriptions can be processed more conveniently during long-term treatment 4, 5
• Particularly valuable for patients at risk for substance abuse or who prefer non-controlled substances 4, 5
• No QT interval prolongation 4, 5

Setting Appropriate Patient Expectations

Atomoxetine requires daily dosing to build and maintain therapeutic levels—unlike stimulants, it cannot be used intermittently or on an as-needed basis. 8 Patients must understand that symptom improvement requires consistent daily administration at adequate doses for sufficient duration (4-6 weeks at target dose). 3