Converting Adderall 55mg Daily to Vyvanse
Do not add Vyvanse to Adderall 55mg—instead, switch completely from Adderall to Vyvanse using a direct conversion without overlap, as combining these amphetamine-based stimulants would result in excessive total amphetamine exposure and significantly increased cardiovascular and psychiatric risks. 1
Why Combination is Contraindicated
- The American Academy of Child and Adolescent Psychiatry explicitly recommends avoiding the combination of Adderall and Vyvanse due to excessive total amphetamine exposure and increased risk of cardiovascular and psychiatric adverse effects 1
- Your current Adderall dose of 55mg already exceeds the maximum recommended daily amphetamine dose of 40-50mg total for adults, making any addition of Vyvanse particularly dangerous 1
Recommended Switching Protocol
Direct conversion approach:
- Stop Adderall completely and initiate Vyvanse the following morning without any overlap period 2
- Both medications are amphetamine-based with similar rapid-acting pharmacokinetic properties (peak concentration 1-3 hours, half-life ~2 hours for the active metabolite), making gradual cross-titration unnecessary 2
- Vyvanse is a prodrug that converts to d-amphetamine through enzymatic hydrolysis in red blood cells, providing a smoother, longer duration of action (up to 14 hours) compared to immediate-release formulations 3, 4
Starting dose considerations:
- Begin Vyvanse at 30mg daily in the morning as the initial dose 5
- This conservative starting point allows assessment of tolerability despite your higher previous Adderall exposure, as Vyvanse's prodrug mechanism provides different pharmacodynamics 6
- The 30mg starting dose is standard regardless of previous stimulant exposure because individual response to different stimulant formulations is variable and unpredictable 2
Dose Titration Strategy
- Titrate Vyvanse upward in 10-20mg increments weekly if tolerated and therapeutic response is inadequate 1
- The maximum approved dose of Vyvanse is 70mg daily for adults with ADHD 1, 3
- Allow at least one week at each dose level before making adjustments to properly assess both therapeutic response and tolerability 7
- Most patients achieve optimal response between 50-70mg daily 5
Monitoring Requirements During Transition
Essential monitoring parameters:
- Check blood pressure and pulse at each dose adjustment and regularly thereafter 1, 7
- Monitor weight systematically, as decreased appetite is a common adverse effect 5
- Use standardized ADHD rating scales (such as ADHD-RS-IV) to objectively assess therapeutic response 7, 5
- Schedule follow-up within 2-4 weeks post-conversion to assess response and tolerability 7
Red flag symptoms requiring immediate discontinuation:
- Cardiovascular symptoms including chest pain, palpitations, or syncope would contraindicate further stimulant use 1
- Significant psychiatric adverse effects such as severe anxiety, agitation, or mood changes 1
Common Pitfalls to Avoid
- Never use a 1:1 conversion ratio from Adderall to Vyvanse—start conservatively at 30mg regardless of previous dose 5
- Do not overlap medications during the switch, as this creates dangerous cumulative amphetamine exposure 1
- Do not calculate doses based on body weight, as stimulant dose variations have not been found to correlate with height or weight 2
- Monitor for insomnia and decreased appetite particularly during the first few days, as these are the most common adverse effects 5
Alternative Considerations if Vyvanse is Inadequate
- If Vyvanse at maximum dose (70mg) provides inadequate symptom control, consider switching to methylphenidate-based stimulants rather than increasing amphetamine exposure further 1, 2
- Non-stimulant options including atomoxetine, guanfacine, or bupropion should be considered if stimulants are ineffective or poorly tolerated 1
- More than 90% of patients respond to one psychostimulant when both methylphenidate and amphetamine classes are tried sequentially 2