Strattera Dose Increase from 18mg to 36mg in a 10-Year-Old
Yes, you can increase from 18mg to 36mg, but this represents a doubling of the dose which is more aggressive than standard titration—a more conservative approach would be to increase to 25mg or 30mg first, then reassess after 1-2 weeks before advancing to 36mg if needed. 1
Standard Dosing Algorithm for Atomoxetine in Children
Target dosing for atomoxetine in children is 1.2 mg/kg/day, which can be administered once daily or divided into two doses. 2
- For a typical 10-year-old weighing approximately 30-35 kg, the target dose would be 36-42 mg/day 1
- The current dose of 18mg is below the typical therapeutic target for most children in this age range 2
- Atomoxetine demonstrates dose-proportional increases in plasma exposure, meaning doubling the dose will approximately double drug levels 3
Recommended Titration Strategy
The safest approach is stepwise dose escalation rather than doubling:
- Start with smaller incremental increases (e.g., 18mg → 25mg → 30mg → 36mg) over 1-2 week intervals 1
- Monitor for adverse effects at each dose level, particularly gastrointestinal symptoms (nausea, abdominal pain), decreased appetite, and somnolence 1, 2
- Assess symptom improvement using standardized rating scales (ADHD-RS or Conners scales) from both parents and teachers before each dose adjustment 4
Critical Monitoring Parameters
Check the following at baseline, 1 week after dose change, and with subsequent adjustments:
- Heart rate and blood pressure (atomoxetine causes modest increases in both parameters) 1, 5
- Appetite and weight (decreased appetite is common, though long-term growth effects normalize) 1, 2
- Mood changes or suicidal ideation (black-box warning for increased suicidal thoughts in pediatric patients) 1
Pharmacokinetic Considerations
CYP2D6 metabolizer status significantly affects atomoxetine levels:
- Extensive metabolizers (most patients) have a half-life of 5.2 hours and clearance of 0.35 L/h/kg 3
- Poor metabolizers (7-10% of population) have a half-life of 21.6 hours and 10-fold higher steady-state concentrations 3
- If this patient is a poor metabolizer (unknown unless tested), the 36mg dose could result in disproportionately high drug levels 3
- Consider more conservative titration if the patient experienced significant side effects at 18mg, as this may indicate poor metabolizer status 1
Common Pitfalls to Avoid
- Avoid rapid dose escalation without adequate monitoring period—give at least 1-2 weeks at each dose level to assess both efficacy and tolerability 1
- Don't ignore cardiovascular monitoring—while increases in heart rate and blood pressure are typically modest and well-tolerated, they require documentation 5
- Don't forget to obtain teacher ratings—school performance is a critical outcome measure and home ratings alone are insufficient 4
Duration of Action Advantage
Atomoxetine provides all-day coverage with once-daily morning dosing, extending through evening hours and into the next morning, which is particularly valuable for homework completion and morning routines. 2