When should the dose of Vyvanse (lisdexamfetamine) be increased versus adding a second dose in the afternoon for a patient with Attention Deficit Hyperactivity Disorder (ADHD)?

When to Increase Vyvanse Dose vs Adding an Afternoon Dose

Increase the morning dose of Vyvanse first when ADHD symptoms are inadequately controlled throughout the day, and only add a second afternoon dose (using short-acting stimulant) if symptoms are well-controlled during most of the day but wear off in late afternoon/evening.

Primary Strategy: Dose Optimization Through Titration

• Start by titrating the morning Vyvanse dose upward in 10-20 mg increments weekly until optimal symptom control is achieved or the maximum dose of 70 mg is reached 1, 2.
• Lisdexamfetamine provides 13-14 hours of continuous symptom coverage when properly dosed, making it designed for once-daily administration without requiring supplemental dosing 2, 3.
• The American Academy of Child and Adolescent Psychiatry recommends systematic titration protocols where doses are increased weekly based on symptom response and tolerability, with adults typically requiring 30-70 mg daily for optimal control 1, 2.

When to Add an Afternoon Dose Instead

• Add a short-acting stimulant (5-10 mg immediate-release methylphenidate or amphetamine) in the afternoon only when:

  • The patient has good symptom control for most of the day on their current Vyvanse dose 4
  • Symptoms specifically return in late afternoon/evening (after 12-14 hours) 4, 1
  • Increasing the morning Vyvanse dose causes intolerable side effects (insomnia, appetite suppression, anxiety) 4
  • The patient is already at maximum Vyvanse dose (70 mg) but needs extended evening coverage 1

• The American Academy of Child and Adolescent Psychiatry explicitly recommends adding a third afternoon dose "at clinician's discretion" to help with homework and evening social activities when the long-acting formulation wears off 4.

Critical Decision Algorithm

Step 1: Assess Current Symptom Pattern

• Obtain weekly symptom ratings documenting when during the day symptoms are most problematic 1.
• If symptoms are present throughout the entire day (morning through evening), this indicates underdosing requiring morning dose increase 1.
• If symptoms are well-controlled until late afternoon then return, this suggests appropriate morning dosing with wearing-off effect 4.

Step 2: Evaluate Current Dose Adequacy

• Adults typically require 30-70 mg daily of lisdexamfetamine for optimal response 2.
• If the patient is on less than 50 mg, increase the morning dose first as they likely have room for optimization 1, 2.
• Maximum daily doses can reach 70 mg, and some patients require this full dose for adequate control 2.

Step 3: Monitor for Side Effects

• Track blood pressure, pulse, sleep quality, and appetite at each visit during titration 1.
• If increasing the morning dose causes insomnia despite good daytime control, consider adding afternoon supplementation instead of further morning increases 4.

Common Pitfalls to Avoid

• Do not add an afternoon dose prematurely when the morning dose is subtherapeutic - this creates unnecessary polypharmacy when simple dose optimization would suffice 1.
• Do not assume 30-40 mg is adequate - many adults require 50-70 mg for optimal symptom control, and underdosing is more common than overdosing 2.
• Avoid scheduling any afternoon supplemental dose after 3 PM to minimize insomnia risk 4.
• Never use a second full dose of Vyvanse in the afternoon - the prodrug mechanism makes this inappropriate; use immediate-release formulations for supplementation 4, 5, 6.

Monitoring During Adjustment

• Schedule weekly contact during titration phase to assess symptom response and side effects 1.
• Use standardized ADHD rating scales to objectively track improvement rather than relying solely on subjective reports 4, 1.
• Document specifically when symptoms occur relative to dosing time to distinguish inadequate dosing from wearing-off effects 4, 1.
• Monitor for tolerance development, though this is rare with proper therapeutic use 1.

Special Considerations

• Lisdexamfetamine's prodrug mechanism provides smoother onset and may have less rebound symptoms compared to immediate-release formulations, making it ideal for once-daily dosing 6, 3.
• The medication remains pharmacologically inactive until enzymatically converted to d-amphetamine in red blood cells, providing rate-limited release over 13-14 hours 5, 2, 6.
• Adults may have continuous functional requirements (work, driving, childcare, household responsibilities) extending into evening hours that justify extended coverage 7.