Recommended Adderall Dose When Switching from Vyvanse 50mg
When switching from Vyvanse 50mg to Adderall, start with Adderall XR 20mg once daily in the morning, or Adderall IR 10mg twice daily (total 20mg/day), then titrate upward by 5-10mg weekly increments based on symptom control and tolerability. 1, 2
Conversion Rationale
- Vyvanse (lisdexamfetamine) 50mg is a prodrug that converts to approximately 20mg of dextroamphetamine after first-pass metabolism 3, 4
- Adderall contains a 3:1 ratio of dextroamphetamine to levoamphetamine salts, making direct milligram-to-milligram conversion inappropriate 5
- The equivalent starting dose of Adderall for a patient on Vyvanse 50mg is approximately 20mg total daily dose, which accounts for the pharmacokinetic differences between the two formulations 1, 6
Specific Dosing Recommendations
For Adderall XR (Extended-Release):
- Start with 20mg once daily in the morning 1, 2
- Increase by 5mg weekly increments if symptom control is inadequate 1, 2
- Maximum dose: 50mg daily 1, 2
For Adderall IR (Immediate-Release):
- Start with 10mg twice daily (7:30 AM and 11:30 AM) 1, 5
- Increase by 5mg per dose weekly if needed 1, 2
- Maximum dose: 50mg daily (typically divided into 2-3 doses) 1, 2
Duration of Action Considerations
- Vyvanse provides approximately 12 hours of symptom control 3, 4
- Adderall XR provides 10.5-12 hours of efficacy, making it the preferred formulation for once-daily dosing comparable to Vyvanse 6, 5
- Adderall IR lasts only 4-6 hours per dose, requiring multiple daily administrations for full-day coverage 6, 5
Titration Protocol
- Allow at least one week between dose increases to properly evaluate therapeutic response and side effects 1
- Assess ADHD symptoms using standardized rating scales (ADHD-RS-IV) at each adjustment 1, 3
- Monitor for common adverse effects including decreased appetite, insomnia, headache, irritability, and cardiovascular changes 1, 3, 7
Monitoring Requirements
- Obtain baseline blood pressure, pulse, height, and weight before initiating Adderall 1, 2
- Check blood pressure and pulse quarterly in adults 1, 2
- Weigh patient at each visit to monitor for appetite suppression 1, 2
- Schedule follow-up visits at least monthly until symptoms stabilize 1, 6
Common Pitfalls to Avoid
- Do not start at the full Vyvanse-equivalent dose (30-40mg Adderall) - this increases risk of cardiovascular side effects and poor tolerability 1, 7
- Do not assume 1:1 mg conversion - Vyvanse is a prodrug requiring metabolic activation, while Adderall is immediately active 3, 4
- Avoid afternoon/evening dosing of IR formulations after 3 PM to minimize sleep disturbances 1, 5
- Do not exceed 50mg daily maximum - if inadequate response occurs at maximum dose, switch to alternative medication rather than increasing further 1, 2
Special Considerations
- Adderall has higher abuse potential compared to Vyvanse due to immediate bioavailability versus prodrug activation 3, 4
- Patients with active substance use disorder should not receive Adderall XR 1
- Amphetamines increase systolic blood pressure by approximately 2 mmHg and diastolic by 1.8 mmHg, with heart rate increasing by 3.7 beats per minute - monitor cardiovascular parameters closely 7