Converting from Adderall XR 20mg to Vyvanse: Dosing Recommendations
When switching from Adderall XR 20mg to Vyvanse (lisdexamfetamine), the recommended starting dose is 30mg once daily in the morning.
Rationale for Dosing Conversion
Vyvanse is a prodrug that is converted to dextroamphetamine in the body. The conversion from Adderall XR to Vyvanse requires understanding the pharmacokinetic differences between these medications:
- Adderall XR 20mg contains mixed amphetamine salts (both dextroamphetamine and levoamphetamine)
- Vyvanse contains lisdexamfetamine which is converted to dextroamphetamine only
- The FDA-approved starting dose for Vyvanse is 30mg once daily 1
Dosing Protocol
- Initial Conversion: Start with Vyvanse 30mg once daily in the morning
- Titration Schedule:
- Assess response after approximately one week
- If needed, increase in increments of 10mg or 20mg at weekly intervals
- Maximum recommended dose is 70mg once daily 1
Administration Guidelines
- Take Vyvanse in the morning to avoid insomnia
- Can be taken with or without food (unlike Adderall XR, Vyvanse's absorption is not significantly affected by food intake) 1, 2
- May be swallowed whole or opened and contents mixed with yogurt, water, or orange juice 1
Monitoring Parameters
- Assess for symptom control throughout the day
- Monitor for common side effects:
- Decreased appetite
- Insomnia
- Headache
- Irritability
- Weight loss
Important Considerations
- Vyvanse has a longer duration of action (10-14 hours) compared to Adderall XR (10-12 hours)
- Vyvanse may provide more consistent drug levels throughout the day due to its prodrug mechanism 1
- The conversion is not exactly equivalent - individual response may vary and dose adjustments may be necessary
Cautions and Contraindications
- Avoid in patients with:
- Known hypersensitivity to amphetamine products
- Concurrent use of MAOIs or within 14 days of MAOI use
- Severe cardiovascular disease 1
Practical Tips
- If switching mid-treatment, discontinue Adderall XR the day before starting Vyvanse
- Morning dosing is essential to minimize sleep disturbances
- Assess for cardiac risk factors before initiating therapy 3
- The 30mg starting dose balances efficacy with minimizing side effects during the transition
Remember that while 30mg is the recommended starting dose, individual response varies, and dose adjustments may be necessary based on efficacy and tolerability.