Strattera (Atomoxetine) Dosing and Treatment Guidelines for ADHD
Recommended Dosage
For children and adolescents up to 70 kg, start atomoxetine at 0.5 mg/kg/day and titrate after a minimum of 3 days to a target dose of 1.2 mg/kg/day, with a maximum of 1.4 mg/kg/day or 100 mg daily, whichever is less. 1, 2, 3
For children and adolescents over 70 kg and adults, start at 40 mg/day, titrate to a target of 80 mg/day, with a maximum of 100 mg/day. 3
Dosing Schedule Options
- Atomoxetine can be administered as a single daily dose (morning or evening) or split into two evenly divided doses to reduce side effects such as initial somnolence. 1, 4, 5
- Single morning dosing provides symptom control throughout the day and into the evening, demonstrating "around-the-clock" effects without the peaks and valleys of stimulant medications. 1, 4
Dose Adjustments Required
- In patients taking strong CYP2D6 inhibitors (such as paroxetine) or in known CYP2D6 poor metabolizers, reduce the dose as these patients have approximately 10-fold higher plasma concentrations and slower elimination. 3, 6
- In hepatic impairment, dose reduction is necessary due to increased atomoxetine exposure. 3, 6
Position in Treatment Algorithm
Stimulant medications remain first-line therapy for ADHD due to larger effect sizes (~1.0 for stimulants vs ~0.7 for atomoxetine), with atomoxetine positioned as second-line treatment. 7, 1 The evidence for stimulants is particularly strong, while evidence for atomoxetine is sufficient but less robust. 7
When to Consider Atomoxetine as First-Line
Atomoxetine should be considered as initial therapy in specific clinical situations: 7, 1
- Patients with comorbid substance use disorders or at risk for substance abuse
- Patients with tic disorders or Tourette's syndrome
- Adolescents at risk for medication diversion (atomoxetine has no abuse potential and is not a controlled substance) 7, 4, 5
- Patients with comorbid anxiety disorders 4
- When stimulant-related sleep disturbances are a concern 1
Age-Specific Recommendations
Preschool-Aged Children (4-5 years)
Atomoxetine is NOT recommended for preschool-aged children as it has not received sufficient rigorous study in this population. 7, 2 For this age group, evidence-based behavioral therapy should be first-line treatment. 7
Elementary School-Aged Children (6-11 years)
Prescribe FDA-approved ADHD medications (stimulants preferred, atomoxetine as alternative) along with parent-administered and/or behavioral classroom interventions. 7 Educational interventions including IEP or 504 plans are necessary components of treatment. 7
Adolescents (12-18 years)
Prescribe FDA-approved ADHD medications with the adolescent's assent, preferably combined with behavioral interventions. 7 Monitor closely for medication diversion, particularly with stimulants. 7
Critical Safety Monitoring
Black Box Warning: Suicidal Ideation
The FDA requires a black box warning for increased risk of suicidal ideation in children and adolescents taking atomoxetine. 2, 3, 4 Monitor closely for suicidality, clinical worsening, and unusual behavior changes, especially during the first few months of treatment or with dose changes. 2, 3
Cardiovascular Monitoring
Obtain personal and family cardiac history before starting atomoxetine. 8, 2 Consider ECG if cardiac risk factors are present. 8 Monitor blood pressure and heart rate regularly, as atomoxetine causes modest increases in both parameters. 3, 4
Hepatic Monitoring
Discontinue atomoxetine and do not restart if jaundice or laboratory evidence of liver injury develops. 3 Rare cases of serious liver injury have been reported. 4
Growth Monitoring
Monitor height and weight in pediatric patients, as atomoxetine has been linked to growth delays in the first 1-2 years of treatment, though growth typically normalizes long-term. 2, 4
Common Adverse Effects
The most common adverse effects include: 2, 3, 4
- Decreased appetite
- Gastrointestinal symptoms (nausea, abdominal pain, vomiting)
- Somnolence (particularly early in treatment)
- Headache
- Fatigue
In adults, additional common effects include: 5, 9
- Dry mouth
- Insomnia
- Constipation
- Dizziness
- Sexual dysfunction
- Urinary hesitancy
These adverse effects are generally mild to moderate and often transient. 10, 4
Expected Timeline for Response
Atomoxetine has a delayed onset of therapeutic effect requiring 6-12 weeks for full benefit, unlike stimulants which work within hours. 1 Assess treatment response after 6-12 weeks of therapy. 1 This delayed onset requires patience and clear communication with patients and families about expectations.
Titration Strategy
Titrate doses to achieve maximum benefit with minimum adverse effects. 7 Start at 0.5 mg/kg/day, increase after minimum 3 days to target of 1.2 mg/kg/day. 2, 3 Dose adjustments are typically made every 7-14 days. 1
Discontinuation
Atomoxetine can be discontinued without tapering, as there is no evidence of symptom rebound or acute discontinuation syndrome. 10, 4 This contrasts with alpha-2 agonists like guanfacine, which require tapering. 8
Contraindications
Absolute contraindications include: 3
- Hypersensitivity to atomoxetine
- Use within 2 weeks of MAOI discontinuation
- Narrow-angle glaucoma
- Pheochromocytoma or history thereof
- Severe cardiovascular disorders that might deteriorate with increases in heart rate and blood pressure
Special Populations
Patients with Comorbid Conditions
Atomoxetine efficacy is not affected by comorbid disorders such as oppositional defiant disorder, conduct disorder, or anxiety, and may improve symptoms of these conditions. 10, 4
Patients with Autism Spectrum Disorder
Atomoxetine demonstrates efficacy in patients with comorbid ASD and ADHD and may be particularly useful when stimulant-related sleep disturbances are problematic. 1