No Immediate-Release (IR) Version of Vyvanse Exists
There is no immediate-release (IR) version of Vyvanse (lisdexamfetamine). Vyvanse is uniquely designed as a prodrug that is only converted to its active form d-amphetamine after ingestion through an enzymatic process predominantly associated with red blood cells 1, 2.
How Vyvanse Works
- Lisdexamfetamine is a prodrug that remains pharmacologically inactive until it undergoes enzymatic conversion in the blood to release d-amphetamine and the amino acid lysine 1, 2
- This unique pharmacological property gives Vyvanse its long-acting characteristics, allowing for once-daily dosing 2
- The conversion process occurs gradually in the bloodstream, not in the digestive tract, which contributes to its extended duration of action 1
Clinical Implications of Vyvanse's Prodrug Design
- Vyvanse was specifically developed as a long-acting stimulant medication with a duration of efficacy up to 14 hours post-dose in adults 2
- The prodrug design was intentionally created to reduce potential for abuse compared to immediate-release stimulant formulations 3
- The pharmacokinetic properties of lisdexamfetamine make extraction of the stimulant component more difficult compared to other stimulant medications 4
Alternative Immediate-Release Options
- For patients requiring an immediate-release stimulant option, Adderall IR is available with a recommended starting dose of 5 mg twice daily 3
- Adderall IR tablets can be safely cut for dose titration when finding the optimal therapeutic dose 3
- The maximum recommended daily dose of Adderall IR is 50 mg according to guidelines 3
Important Considerations
- Vyvanse is typically started at 20-30 mg once daily in the morning, with titration involving increasing by 10 mg weekly to a maximum of 70 mg daily 4
- Due to its prodrug nature, attempting to convert Vyvanse to an immediate-release formulation by crushing or altering the medication would not be effective, as the enzymatic conversion process still needs to occur in the bloodstream 1, 2
- The American Academy of Pediatrics suggests that lisdexamfetamine may be preferred over other stimulants in adolescents due to its lower abuse potential 4