What is the proper usage and dosage of Dextroamphetamine (amphetamine) for treating Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy?

Dextroamphetamine Dosing and Administration

For ADHD, start dextroamphetamine at 5 mg once or twice daily in children ≥6 years (2.5 mg daily for ages 3-5), titrating by 5 mg weekly to a maximum of 40 mg/day, with first dose given upon awakening and additional doses at 4-6 hour intervals. 1

ADHD Treatment Dosing

Pediatric Dosing (Ages 3-5 Years)

• Starting dose: 2.5 mg daily 2, 1
• Titration: Increase by 2.5 mg weekly until optimal response 2, 1
• Administration: Give first dose upon awakening; additional doses (1-2) at 4-6 hour intervals 1

Pediatric Dosing (Ages 6+ Years)

• Starting dose: 5 mg once or twice daily (morning and lunch) 2, 1
• Titration: Increase by 5 mg weekly increments 2, 1
• Maximum dose: Rarely exceeds 40 mg total daily; only exceed this when clearly documented that symptoms cannot be controlled at lower doses without side effects 2, 1
• Weight consideration: For children <25 kg, single doses should not exceed 10 mg 2

Adolescent and Adult Dosing (Ages 12+ Years)

• Starting dose: 10 mg daily 2
• Titration: Increase by 5 mg weekly 2
• Administration: First dose upon awakening, additional doses at 4-6 hour intervals 1

Formulation Options

• Immediate-release: 5 mg twice daily, allows flexible dosing 3, 1
• Extended-release (Spansule): 10 mg once daily in morning, increase by 5 mg increments 3
• Maximum total daily dose: 50 mg per day for extended-release formulations 3

Narcolepsy Treatment Dosing

Pediatric (Ages 6-12 Years)

• Starting dose: 5 mg daily 1
• Titration: Increase by 5 mg weekly until optimal response 1

Adolescent and Adult (Ages 12+ Years)

• Starting dose: 10 mg daily 1
• Titration: Increase by 10 mg weekly until optimal response 1
• Usual effective range: 5-60 mg per day in divided doses 1
• Administration: First dose upon awakening, additional doses at 4-6 hour intervals 1

Research evidence suggests that 10-30 mg daily effectively reduces narcolepsy attacks by approximately 50%, with 30 mg showing only marginally greater benefit than 10 mg 4

Critical Pre-Treatment Assessment

Before initiating dextroamphetamine, you must assess for cardiac disease through careful personal and family history (particularly sudden death or ventricular arrhythmia), physical examination, baseline blood pressure, pulse, height, and weight. 2, 1

Additional mandatory screening includes:

• Family history and clinical evaluation for motor/verbal tics or Tourette's syndrome 1
• Baseline vital signs and growth parameters 2

Titration Strategy and Monitoring

Standard Titration Approach

• Start at recommended initial dose based on age 2
• Increase weekly by 2.5-5 mg increments depending on age group 2
• Use standardized ADHD rating scales from parents and teachers before each dose increase 2

Forced Titration Trial (Alternative Method)

• Patient takes all dose levels with each dose lasting 1 week 2
• Collect rating scales at each dose level 2
• This approach systematically identifies optimal dosing 2

Ongoing Monitoring Requirements

• Assess blood pressure, pulse, height, and weight at each visit 2
• Obtain standardized ADHD rating scales through phone contact between visits if needed 2
• Periodically interrupt drug administration to determine if behavioral symptoms recur, requiring continued therapy 1

Important Clinical Considerations and Warnings

Side Effect Profile

Dextroamphetamine produces greater effects on appetite and sleep compared to methylphenidate due to longer excretion half-lives. 2

Common adverse effects requiring dose reduction include:

• Insomnia (avoid late evening doses) 1
• Anorexia 1
• Cardiovascular effects (tachycardia, hypertension) 5

Response Rates and Alternative Options

• Approximately 70% of children respond to either dextroamphetamine or methylphenidate alone 2
• Nearly 90% respond if both medications are tried 2
• Consider switching to methylphenidate if inadequate response or intolerable side effects occur 2

Safety Concerns

Amphetamines are DEA Schedule II controlled substances with high abuse potential 5. Serious cardiovascular events including myocardial infarction have been reported, particularly when combined with alcohol 6. Signs of overdose include hyperactivity, hyperthermia, tachycardia, tremors, and seizures 5.

Special Populations

Pregnancy and Lactation:

• Amphetamines do not appear associated with major congenital malformations or cardiac malformations 3
• Possible small increased risk for gastroschisis (aOR 3.0,95% CI 1.2-7.4), preeclampsia (aRR 1.29), and preterm birth when used in second half of pregnancy (aRR 1.30) 3
• Lactation category L3; monitor infants for irritability, insomnia, and feeding difficulty 3

Dosing Pitfalls to Avoid

• Never exceed 40 mg daily without clear documentation that lower doses failed and higher doses produce no side effects 2
• Avoid late evening administration due to insomnia risk 1
• Do not use in children under 3 years for ADHD 1
• Single doses should not exceed 10 mg in children weighing <25 kg 2