Strattera (Atomoxetine) Starting Dose and Side Effects
Start atomoxetine at approximately 0.5 mg/kg/day for children and adolescents weighing up to 70 kg, then titrate after a minimum of 3 days to a target dose of 1.2 mg/kg/day (maximum 1.4 mg/kg/day or 100 mg/day, whichever is lower), administered either once daily in the morning or split into two divided doses. 1
Dosing Algorithm
Initial Dosing Strategy
- Children/Adolescents ≤70 kg: Begin at ~0.5 mg/kg/day
- Children/Adolescents >70 kg and Adults: Start at 40 mg/day
- Titration timeline: Wait minimum 3 days before increasing dose
- Target dose: 1.2 mg/kg/day (shown most effective in clinical trials)
- Maximum dose: 1.4 mg/kg/day or 100 mg/day, whichever is lower 1
Administration Options
You can dose atomoxetine either:
- Once daily in the early morning (proven effective through evening hours) 2
- Twice daily (early morning and late afternoon/early evening) to minimize gastrointestinal side effects 1
Critical caveat: Avoid rapid dose escalation—this significantly increases gastrointestinal adverse effects, particularly nausea and vomiting 3. The evidence shows that slower titration improves tolerability without compromising efficacy.
Side Effects Profile
Most Common Adverse Effects (occurring in clinical trials)
The following side effects occur most frequently in children and adolescents 1:
- Nausea (most common, especially with rapid titration)
- Vomiting
- Decreased appetite
- Abdominal pain
- Fatigue/Somnolence (particularly at treatment initiation)
- Headache
Serious Warnings and Monitoring Requirements
Black Box Warning—Suicidal Ideation: Meta-analysis of 12 placebo-controlled trials demonstrated increased risk of suicidal ideation in children and adolescents receiving atomoxetine 1. You must closely monitor all pediatric patients for suicidality, clinical worsening, and unusual behavioral changes, especially during the first few months of treatment or at times of dose changes. This risk was NOT observed in adult trials 1.
Cardiovascular Effects
Atomoxetine causes:
- Increased heart rate and blood pressure (unlike alpha-2 agonists which decrease these parameters) 3
- Before initiating treatment, obtain personal and family cardiac history including: sudden death, cardiovascular symptoms, Wolff-Parkinson-White syndrome, hypertrophic cardiomyopathy, and long QT syndrome 3
- If risk factors present, obtain ECG and consider cardiology referral before starting medication 3
Other Important Adverse Effects
- Growth effects: Initial delays in height/weight gain during first 1-2 years, with return to expected trajectories after 2-3 years of treatment 3
- Hepatotoxicity: Extremely rare but serious—monitor for jaundice, dark urine, right upper quadrant tenderness 3
- Psychiatric symptoms: Monitor for emergent psychotic/manic symptoms, aggressive behavior, or hostility 1
Special Population Considerations
CYP2D6 Poor Metabolizers (~7% of population): These patients have significantly higher plasma levels and longer half-lives, leading to increased adverse effects 1. Consider genetic testing or dose reduction if excessive side effects occur. Drug interactions with CYP2D6 inhibitors (e.g., paroxetine, fluoxetine) produce similar effects 1.
Discontinuation
No symptom rebound or acute discontinuation syndrome has been observed with atomoxetine, unlike stimulants 4. However, monitor for return of ADHD symptoms after stopping treatment.
Clinical Context
Atomoxetine represents the first FDA-approved non-stimulant for ADHD and is particularly valuable for:
- Patients at risk for substance abuse (no abuse potential, not a controlled substance) 4
- Comorbid anxiety or tic disorders 5
- Patients who cannot tolerate or do not respond to stimulants 6
- Situations where controlled substance prescribing is problematic
The evidence shows atomoxetine is less effective than extended-release stimulants (OROS methylphenidate, extended-release mixed amphetamine salts) but comparable to immediate-release methylphenidate 4. The trade-off is lower efficacy for better safety profile in specific populations.