Switching from Vyvanse 40 mg to Adderall XR
When switching from Vyvanse 40 mg to Adderall XR, start with 10 mg once daily in the morning and titrate by 5 mg weekly based on clinical response. 1
Rationale for Starting Dose
The American Academy of Child and Adolescent Psychiatry recommends starting Adderall XR at 10 mg once daily regardless of prior stimulant exposure, as this minimizes side effects and allows proper assessment of response. 1 While Vyvanse 40 mg converts to approximately 12-15 mg of dextroamphetamine after enzymatic hydrolysis 2, 3, direct dose conversion is not recommended because:
- Pharmacokinetic differences exist: Vyvanse has a 0.6-1.1 hour longer lag time and delayed peak compared to amphetamine formulations, but produces similar total drug exposure and peak effects 2
- Starting low prevents unnecessary side effects that decrease medication adherence 1
- Individual response varies significantly between different amphetamine formulations despite similar pharmacodynamics 4
Titration Protocol
Week-by-week approach:
- Week 1: Start 10 mg once daily in the morning 1
- Week 2: Increase to 15 mg if inadequate response 1
- Week 3: Increase to 20 mg if needed 1
- Week 4+: Continue titrating by 5 mg weekly up to maximum 40-50 mg daily 1
Allow at least one week between dose increases to properly evaluate therapeutic response and side effects. 1
Administration Guidelines
- Take in the morning to minimize sleep disturbances 1
- Once-daily dosing eliminates need for in-school or afternoon doses and improves adherence 1
- Maximum recommended dose is 40-50 mg daily 1
Monitoring Requirements
At each visit or dose increase:
- Assess therapeutic effects and side effects 1
- Check blood pressure and pulse 1
- Monitor weight for appetite suppression 1
For adults on stimulants: Blood pressure and pulse should be checked quarterly 1
Common Pitfalls to Avoid
- Do not start at higher doses (e.g., attempting direct conversion from Vyvanse 40 mg to Adderall XR 20 mg) as this leads to unnecessary side effects 1
- Do not increase doses too quickly without allowing sufficient time to evaluate response 1
- Do not exceed maximum recommendations (40-50 mg) if medication is ineffective—consider alternative medications instead 1
- Do not administer in afternoon or evening as this causes sleep disturbances 1
Comparative Efficacy Data
Research demonstrates that lower doses of Adderall can produce effects comparable to higher doses of other stimulants—specifically, 7.5 mg Adderall produced effects similar to 17.5 mg Ritalin in pediatric studies. 4 This supports the conservative starting approach, as Adderall formulations may be functionally more potent than expected based on simple dose conversion. 4