Switching from Vyvanse 70 mg to Adderall XR
When switching from Vyvanse (lisdexamfetamine) 70 mg to Adderall XR, start with Adderall XR 30 mg once daily in the morning, as this represents an approximately equivalent amphetamine dose based on the prodrug conversion ratio. 1
Dosing Rationale
Vyvanse 70 mg is a prodrug that converts to approximately 20.8 mg of d-amphetamine after enzymatic hydrolysis 2. Since Adderall XR contains a 3:1 ratio of d-amphetamine to l-amphetamine salts, and considering the FDA labeling for switching patients from other medications, the recommended starting dose when switching is either 20-30 mg of Adderall XR 1.
Specific Switching Protocol:
- For adults: Start with Adderall XR 20-30 mg once daily upon awakening 1
- For adolescents (13-17 years): Start with Adderall XR 20 mg once daily, which can be increased after one week if needed 1
- For children (6-12 years): Start with Adderall XR 10 mg once daily, as the maximum recommended dose is 30 mg/day 1
Implementation Strategy
Direct switch without washout period: The FDA labeling explicitly states that patients switching from another medication should start at the recommended dose for their age group 1. No tapering or washout period is required when switching between amphetamine-based stimulants.
Titration schedule: After the initial switch, adjust the dose in weekly increments of 5-10 mg based on symptom control and tolerability 3. Monitor response using:
- Parent and teacher rating scales (for children/adolescents)
- Self-ratings (for adolescents and adults)
- Assessment of target ADHD symptoms 3
Clinical Monitoring
Initial follow-up: Contact the patient weekly during the first 2-4 weeks post-switch to assess efficacy and side effects 3. Key monitoring parameters include:
- Vital signs: Check blood pressure and pulse, as both medications can increase cardiovascular parameters 3, 1
- Appetite and weight: Weigh at each visit to objectively monitor appetite suppression 3
- Sleep: Assess for insomnia, particularly since both are long-acting formulations 3
- Symptom control: Evaluate whether ADHD symptoms remain adequately controlled throughout the day
Important Caveats
Pharmacokinetic differences: While both are extended-release amphetamine formulations, Vyvanse has a smoother pharmacokinetic profile due to its prodrug mechanism 2. Some patients may notice differences in:
- Duration of effect (Vyvanse may provide slightly longer coverage)
- Side effect profile (particularly appetite suppression and sleep disturbance)
- Onset of action (Adderall XR may have slightly faster onset)
Contraindications remain the same: Ensure no contraindications exist including cardiovascular disease, hyperthyroidism, glaucoma, agitated states, or concurrent MAOI use 1.
Dose ceiling: The maximum recommended daily dose of Adderall XR is 30 mg for children, while adolescents and adults may require higher doses, though the FDA label emphasizes 20 mg as the standard adult starting dose when switching 1.
Research data demonstrates comparable efficacy between lisdexamfetamine and mixed amphetamine salts formulations 4, 5, 6, supporting the validity of this direct switch approach with appropriate dose adjustment.