Atomoxetine Treatment Protocol for ADHD
Atomoxetine should be initiated at 0.5 mg/kg/day and titrated to a target dose of 1.2 mg/kg/day (maximum 1.4 mg/kg/day or 100 mg/day, whichever is lower) for optimal efficacy in ADHD treatment. 1, 2
Dosing and Administration
Initial Dosing Strategy
- Start with 0.5 mg/kg/day for children and adolescents up to 70 kg
- Start with 40 mg/day for individuals over 70 kg and adults
- Administer either as a single daily dose in the morning or divided into two evenly spaced doses (morning and late afternoon)
- Continue initial dose for a minimum of 3 days before increasing
Dose Titration
- After initial period, increase to target dose of 1.2 mg/kg/day
- Maximum recommended dose: 1.4 mg/kg/day or 100 mg daily (whichever is lower)
- Full therapeutic effects may take 6-12 weeks to develop 3
- Inadequate dosing (not reaching target dose) can lead to reduced efficacy 3
Special Populations
- For patients with hepatic impairment: Reduce dose by 50%
- For CYP2D6 poor metabolizers or patients taking strong CYP2D6 inhibitors: Slower titration and lower target dose may be required 1, 2
- Not recommended for preschool-aged children (under 6 years) due to insufficient evidence 1
Monitoring and Safety
Cardiovascular Monitoring
- Obtain personal and family cardiac history before initiating treatment
- Consider ECG and possible referral to pediatric cardiologist if cardiac risk factors are present
- Monitor for increased heart rate and blood pressure, which can occur with atomoxetine 1
Psychiatric Monitoring
- BLACK BOX WARNING: Monitor closely for suicidal ideation, especially in children and adolescents during the first few months of treatment 1, 2
- Screen for bipolar disorder before starting treatment
- Watch for emergence of psychotic or manic symptoms
- Monitor for aggressive behavior or hostility 1
Other Monitoring
- Track height and weight in pediatric patients, as atomoxetine has been linked to growth delays in the first 1-2 years of treatment (typically returns to expected trajectory after 2-3 years) 1
- Monitor for signs of liver injury (jaundice, dark urine, right upper quadrant tenderness)
- Assess for urinary hesitancy or retention 1, 2
Common Adverse Effects
- Children and adolescents: nausea, vomiting, fatigue, decreased appetite, abdominal pain, somnolence 1
- Adults: dry mouth, insomnia, nausea, decreased appetite, constipation, dizziness, sexual dysfunction 4
- Most side effects are mild to moderate and often transient 5
- Adverse effects may be more pronounced if dosage is increased too rapidly 1
Clinical Considerations
Advantages Over Stimulants
- Not classified as a controlled substance - beneficial for patients with substance use concerns 3, 4
- Provides "around-the-clock" effects rather than time-limited coverage 3
- May be preferred for patients with comorbid anxiety or tics 5
- Lower risk of insomnia compared to stimulants 5
Potential Use as Adjunctive Therapy
- Limited evidence supports atomoxetine use in combination with stimulant medications when stimulant monotherapy is not fully effective 1
Discontinuation
- Unlike guanfacine and clonidine, atomoxetine does not require tapering when discontinuing 1
- Discontinuation is not associated with symptom rebound 5
Comparative Efficacy
- Comparable efficacy to immediate-release methylphenidate 4, 5
- Less effective than extended-release methylphenidate formulations and extended-release mixed amphetamine salts 5
- Effective for both children/adolescents and adults with ADHD 2, 5
Common Pitfalls to Avoid
Inadequate dosing: Failing to reach the target dose of 1.2 mg/kg/day may result in suboptimal efficacy 3
Impatience with treatment response: Unlike stimulants, full therapeutic effects may take 6-12 weeks to develop 3
Overlooking drug interactions: Atomoxetine is primarily metabolized through CYP2D6; avoid co-administration with CYP2D6 inhibitors (e.g., paroxetine) 1, 5
Insufficient monitoring: Failing to monitor for suicidal ideation, especially during the first few months of treatment 1, 2
Abrupt discontinuation: While not requiring tapering like some other non-stimulants, patients should still be monitored during discontinuation 1