Starting Dose of Vyvanse When Switching from 15mg Adderall
When switching from 15mg of Adderall to Vyvanse, the recommended starting dose is 30mg of Vyvanse once daily in the morning. 1, 2
Rationale for Dose Selection
- The American Academy of Child and Adolescent Psychiatry recommends a starting dose of Vyvanse of 30mg once daily in the morning when transitioning from other stimulant medications 1
- Vyvanse is a prodrug of dextroamphetamine that is converted to the active compound primarily in the blood due to hydrolytic activity of red blood cells 3
- Unlike Adderall (which contains both dextroamphetamine and amphetamine salts), Vyvanse contains only lisdexamfetamine, which converts to dextroamphetamine 4
- The 30mg starting dose provides a smooth transition that minimizes the risk of side effects while maintaining therapeutic efficacy 2
Pharmacokinetic Considerations
- Vyvanse has a longer duration of action (13 hours in children, 14 hours in adults) compared to immediate-release Adderall (4-6 hours) 5
- The prodrug formulation of Vyvanse provides more consistent plasma concentrations throughout the day compared to Adderall 4
- Vyvanse's conversion to dextroamphetamine is not affected by gastrointestinal pH or transit times, leading to more predictable absorption 5
- Peak plasma concentration (Tmax) of dextroamphetamine from Vyvanse occurs approximately 3.5 hours post-dose in children 3
Titration Schedule After Initial Dose
- After starting with 30mg, allow at least one week before considering dose adjustments to properly evaluate response 2
- If needed, the dose can be titrated by increasing in 10-20mg increments at weekly intervals 2
- Maximum recommended daily dose of Vyvanse is 70mg 1, 2
- Titration should be based on clinical response and tolerability, with careful monitoring for side effects 2
Monitoring Parameters
- Assess for common side effects including decreased appetite, insomnia, headache, irritability, and weight loss 4, 6
- Monitor blood pressure and pulse regularly, especially during the initial titration period 2
- Weigh patients at each visit to monitor for appetite suppression 2
- Evaluate both therapeutic benefits and side effects systematically during dose adjustments 2
Special Considerations
- Morning administration is recommended to minimize sleep disturbances 2
- Food does not significantly affect the AUC or Cmax of dextroamphetamine from Vyvanse, but may prolong Tmax by approximately 1 hour 3
- If the 30mg dose proves ineffective after adequate trial, consider increasing to 50mg rather than immediately jumping to the maximum dose 7
- If maximum recommended doses do not provide adequate symptom control, consider reevaluating the diagnosis or exploring alternative medications 2
Common Pitfalls to Avoid
- Starting at too high a dose, which can lead to unnecessary side effects and decreased medication adherence 2
- Not allowing sufficient time between dose increases to evaluate response (minimum one week) 2
- Continuing to increase the dose beyond maximum recommendations when not effective - consider alternative medications instead 2
- Overlooking the importance of morning administration to minimize sleep disturbances 2