What are the treatment options for Attention Deficit Hyperactivity Disorder (ADHD) in pediatric patients with low body weight?

From the Guidelines

Treating ADHD in pediatric patients with low weight requires careful consideration of medication selection and dosing adjustments to minimize potential adverse effects on growth and maximize therapeutic benefits. For these children, stimulant medications like methylphenidate or amphetamine-based medications should be initiated at lower doses than typically recommended, with a starting dose of 0.3-0.5 mg/kg/day for methylphenidate and 0.1-0.3 mg/kg/day for amphetamines 1.

Key Considerations

• Weight-based dosing may be more appropriate than age-based dosing to account for individual variations in metabolism and sensitivity to medication effects.
• Non-stimulant alternatives like atomoxetine, guanfacine, or clonidine may be better tolerated in some low-weight children as they have less impact on appetite and growth 1.
• Regular monitoring of weight, height, blood pressure, and heart rate is essential, with appointments every 2-4 weeks during initial titration and then every 3 months.
• Nutritional support is crucial, offering calorie-dense meals when medication effects are lowest, typically breakfast before medication and dinner/evening snacks.

Medication Selection

• Stimulants have large effect sizes for reducing ADHD core symptoms, but may have limited daily duration of effects and potential for rebound of symptoms when effect wears off in the afternoon/evening 1.
• Non-stimulants like atomoxetine have "around-the-clock" effects, but may have smaller effect size in comparison to stimulants and possible first-line option in comorbid substance use disorders, disruptive behavior disorders, tic/Tourette's disorder 1.

Dosing Adjustments

• Adjustment and changes of the pharmacological treatment regimen are the rule and not the exception, due to changes in symptomatology or the psychosocial situation of the patient, but also due to normal development, e.g., increased weight 1.
• If no desired benefit is observed after adequate treatment with methylphenidate, lisdexamfetamine should be preferred as the next option over non-stimulants 1.

Monitoring and Support

• Medication adherence should be regularly assessed and potential issues in adherence openly discussed, with factors like attitudes of patients and parents toward pharmacological treatment, a trustful physician-patient relationship, family support, and knowledge about the disorder and the intended medication influencing decision making 1.

From the FDA Drug Label

Atomoxetine capsules should be initiated at a total daily dose of approximately 0.5 mg/kg and increased after a minimum of 3 days to a target total daily dose of approximately 1.2 mg/kg administered either as a single daily dose in the morning or as evenly divided doses in the morning and late afternoon/early evening. The total daily dose in children and adolescents should not exceed 1.4 mg/kg or 100 mg, whichever is less

The recommended dose of atomoxetine for pediatric patients of low weight (up to 70 kg) is 0.5 mg/kg initially, increasing to a target dose of 1.2 mg/kg after a minimum of 3 days, with a maximum dose of 1.4 mg/kg or 100 mg, whichever is less 2.

• The dose should be administered either as a single daily dose in the morning or as evenly divided doses in the morning and late afternoon/early evening.
• The dose may need to be adjusted based on the patient's response to the medication and their individual needs.

From the Research

ADHD Treatment in Pediatric Patients of Low Weight

• The treatment of attention-deficit/hyperactivity disorder (ADHD) in pediatric patients of low weight can be challenging, and non-stimulant medications may be considered as an alternative to stimulants 3, 4, 5, 6, 7.
• Atomoxetine is a non-stimulant medication that has been approved for the treatment of ADHD in children and adolescents, and it has been shown to be effective and well-tolerated in this population 3, 4, 6.
• The recommended dosing of atomoxetine is weight-based, and dosages should be adjusted to a target dosage of 1.2 mg/kg/day in children and adolescents weighing 70 kg or less 3.
• Other non-stimulant medications, such as alpha agonists (e.g., guanfacine extended-release, clonidine ER) and norepinephrine reuptake inhibitors (e.g., viloxazine), may also be considered for the treatment of ADHD in pediatric patients of low weight 5, 7.
• Non-stimulant medications can be used as monotherapy or added to a stimulant as an augmentation strategy, and they may be particularly useful for patients who cannot tolerate stimulants or have an incomplete treatment response to stimulants 5, 6, 7.

Safety and Efficacy

• Atomoxetine has been shown to be safe and well-tolerated in pediatric patients with ADHD, with common adverse events including headache, abdominal pain, decreased appetite, vomiting, somnolence, and nausea 3, 4.
• Atomoxetine has also been shown to be effective in improving symptoms of ADHD and health-related quality of life in pediatric patients 3, 4.
• Other non-stimulant medications, such as alpha agonists and norepinephrine reuptake inhibitors, have also been shown to be safe and effective in the treatment of ADHD in pediatric patients 5, 7.

Future Directions

• Research is ongoing to develop new non-stimulant medications for the treatment of ADHD, including monoamine reuptake inhibitors, receptor modulators, and multimodal agents 7.
• These new medications may offer alternative treatment options for pediatric patients with ADHD who cannot tolerate stimulants or have an incomplete treatment response to stimulants 7.