Adderall XR is Extended-Release
Adderall XR is an extended-release formulation, not immediate-release. 1
Formulation Details
The "XR" in Adderall XR stands for "extended-release." This is a once-daily formulation that uses a unique dual-bead delivery system 1:
- Two types of drug-containing beads designed to give a double-pulsed delivery of amphetamines
- First pulse: Immediate-release beads release approximately 50% of the dose upon ingestion
- Second pulse: Delayed-release beads release the remaining 50% approximately 4 hours later
Pharmacokinetic Profile
The extended-release nature is evident in its pharmacokinetics 1:
- Time to peak concentration (Tmax): Approximately 7 hours for Adderall XR
- Comparison: This is about 4 hours longer than immediate-release Adderall (Tmax ~3 hours)
- Duration of action: Provides 12 hours of symptom coverage 2
- Onset: Rapid onset within 1.5 hours despite being extended-release 2
Clinical Equivalence
A single 20 mg dose of Adderall XR provides comparable plasma concentrations to immediate-release Adderall 10 mg given twice daily (at 8 AM and 12 noon), spaced 4 hours apart 1. This makes it suitable for once-daily morning dosing, eliminating the need for midday doses at school or work.
Distinction from Immediate-Release
Regular Adderall (without the XR designation) is the immediate-release formulation. The extended-release technology in Adderall XR was specifically developed to prolong amphetamine release compared to conventional immediate-release tablets 1, 3.