Can atomoxetine be increased above 100 mg per day in a patient with attention‑deficit/hyperactivity disorder?

Atomoxetine Dosing Above 100 mg in Adults with ADHD

No, atomoxetine should not be increased above 100 mg per day in patients with ADHD, as the maximum recommended dose is the lesser of 1.4 mg/kg per day or 100 mg per day—doses above this threshold do not improve efficacy and increase adverse-effect risk. 1

Maximum Dose Ceiling

• The FDA-approved maximum dose is explicitly capped at 100 mg per day (or 1.4 mg/kg per day, whichever is less), and exceeding this limit provides no additional therapeutic benefit while increasing the risk of adverse effects 1, 2
• This ceiling applies regardless of patient weight in adults, as the 100 mg absolute maximum supersedes the weight-based calculation for patients over 70 kg 1

Standard Titration Protocol

• For adults weighing >70 kg, initiate at 40 mg once daily, maintain for at least 7–14 days, then increase to 60 mg daily 1
• If needed after another 7–14 days, escalate to the target dose of 80 mg daily 1
• The 100 mg maximum represents the absolute ceiling, not a routine target dose 1

Evidence for Dose-Response Relationship

• Clinical trials in adults used doses of 60,90, or 120 mg/day, but the FDA label specifically restricts dosing to ≤100 mg/day based on safety and efficacy data 3, 4
• Studies demonstrate that the target therapeutic dose of 1.2 mg/kg/day (approximately 80 mg for a 70 kg adult) achieves maximal symptom reduction 1, 5
• Research on maintenance treatment shows that even lower doses (0.5 mg/kg/day) can maintain response in patients who initially responded to higher doses, suggesting no benefit to pushing beyond established limits 5

Safety Considerations at Higher Doses

• Rapid dose escalation or excessive dosing increases risk of behavioral activation, agitation, motor restlessness, insomnia, impulsiveness, and aggression 1
• Cardiovascular effects (increased heart rate and blood pressure) are dose-related and more pronounced at higher doses 1, 3, 4
• Common adverse effects (nausea, decreased appetite, dry mouth, fatigue) are more frequent and severe at doses approaching or exceeding 100 mg 1, 3, 4

Alternative Strategies if 100 mg is Inadequate

• If response is insufficient at 80–100 mg after 6–12 weeks (the time required for full therapeutic effect), consider switching to a stimulant medication rather than exceeding the maximum atomoxetine dose 1
• Combination therapy with bupropion can be considered if atomoxetine alone is inadequate, though this requires careful monitoring for neuropsychiatric effects and cardiovascular changes 6
• Reassess the diagnosis and evaluate for comorbid conditions (anxiety, depression, substance use) that may be limiting treatment response 1

Common Pitfall to Avoid

• Do not interpret the 1.4 mg/kg/day calculation as permission to exceed 100 mg in heavier adults—the FDA label explicitly states the maximum is "the lesser of" these two values, making 100 mg an absolute ceiling 1, 2