What is the maximum dose of Adderall (amphetamine and dextroamphetamine) combined with Vyvanse (lisdexamfetamine)?

Maximum Dose of Adderall Combined with Vyvanse

The maximum recommended dose when combining Adderall and Vyvanse should not exceed the individual maximum doses of each medication, with Adderall XR having a maximum daily dose of 50 mg and Vyvanse having a maximum daily dose of 70 mg. 1, 2

Individual Maximum Doses

• Adderall XR (amphetamine mixed salts) has a maximum recommended daily dose of 50 mg for adults with ADHD 1, 2
• Vyvanse (lisdexamfetamine) has a maximum recommended daily dose of 70 mg for adults with ADHD 1, 3
• Lisdexamfetamine is a prodrug that is converted to dextroamphetamine after ingestion, meaning both medications ultimately result in amphetamine exposure 1, 4

Safety Considerations for Combined Use

• Combining two stimulant medications that both ultimately result in amphetamine exposure significantly increases the risk of adverse effects including:

  • Cardiovascular effects (increased heart rate, blood pressure) 2, 5
  • Central nervous system effects (insomnia, irritability, anxiety) 2, 5
  • Decreased appetite and weight loss 3, 6
  • Risk of stimulant toxicity with symptoms of hyperactivity, hyperthermia, tachycardia, tremors, and seizures 5

• The American Academy of Child and Adolescent Psychiatry recommends careful monitoring of vital signs when using stimulant medications, particularly when considering combination therapy 2

Clinical Approach to Stimulant Therapy

• Rather than combining two stimulant medications, the preferred approach is to:

  • Optimize the dose of a single stimulant medication first 2
  • If inadequate response at maximum dose, consider switching to the alternative stimulant 2, 7
  • Consider non-stimulant alternatives if stimulants are ineffective or poorly tolerated 2, 7

• When initiating stimulant therapy:

  • Start with low doses (Adderall XR 10 mg or Vyvanse 20-30 mg) 2
  • Titrate gradually (Adderall XR by 5 mg weekly, Vyvanse by 10 mg weekly) 1, 2
  • Assess both therapeutic effects and side effects before each dose increase 2, 7

Important Cautions

• Combining two stimulant medications is generally not recommended in standard clinical practice due to increased risk of side effects without clear evidence of additional benefit 2, 3
• If combination therapy is deemed necessary in exceptional cases, the total amphetamine exposure should be carefully calculated and monitored 5
• Patients should be monitored more frequently when using combination therapy, with particular attention to vital signs, sleep patterns, and appetite 2, 5

Alternative Approaches

• If a patient reaches the maximum dose of one stimulant without adequate symptom control, consider:
  • Switching to the alternative stimulant rather than combining 2
  • Adding a non-stimulant medication (e.g., atomoxetine) 2
  • Reevaluating the diagnosis and considering comorbid conditions 2, 7