Adderall XR 20 mg Once Daily is Equivalent to Adderall IR 10 mg Twice Daily
The equivalent dose of Adderall XR to 20 mg of Adderall IR is 20 mg of Adderall XR taken once daily in the morning. 1, 2
Pharmacokinetic Basis for Equivalence
- Adderall XR contains the same 3:1 ratio of dextroamphetamine to levoamphetamine as Adderall IR, but with a unique two-stage delivery system 1
- The bioavailability and pharmacokinetic profiles of Adderall XR 20 mg are comparable to those of Adderall IR 10 mg taken twice daily 1, 2
- Adderall XR's formulation includes immediate-release pellets that release the first half of the dose upon ingestion and delayed-release pellets that release the second half approximately 4 hours later 1
Clinical Evidence Supporting Equivalence
- A randomized, open-label, crossover study demonstrated that the 20 mg test formulation of extended-release Adderall had comparable pharmacokinetic profiles and bioequivalence in rate and extent of drug absorption to Adderall IR 10 mg twice daily for both d- and l-amphetamine 2
- Adderall XR provides 12 hours of coverage with a rapid onset of action (within 1.5 hours), making it suitable for once-daily dosing 1, 3
Dosing Recommendations
- The American Academy of Child and Adolescent Psychiatry recommends starting with 10 mg of Adderall XR once daily in the morning, with gradual titration by 5 mg weekly increments based on clinical response and tolerability 4
- Morning administration is recommended to minimize sleep disturbances 4, 5
- Allow at least one week between dose increases to properly evaluate response 4, 5
- The maximum recommended daily dose of Adderall XR is 40-50 mg 4, 6
Clinical Advantages of XR Formulation
- Once-daily dosing improves medication adherence by eliminating the need for in-school or afternoon doses 7, 8
- Reduces potential for abuse compared to immediate-release formulations 6
- Provides more consistent coverage throughout the day with fewer peak-trough fluctuations 9
- Eliminates the need for patients to remember to take multiple doses throughout the day 7, 3
Monitoring Considerations
- Assess both therapeutic effects and side effects before each dose increase 5
- Monitor vital signs, including blood pressure and pulse, at baseline and with each dose increase 4, 5
- For adults on stimulants, blood pressure and pulse should be checked quarterly 4, 6
- Weigh patients at each visit to monitor for appetite suppression 4
Common Pitfalls to Avoid
- Starting at too high a dose, which can lead to unnecessary side effects and decreased medication adherence 4, 5
- Not allowing sufficient time between dose increases to evaluate response 4, 5
- Continuing to increase the dose beyond maximum recommendations when not effective - consider alternative medications instead 4, 6, 5
- Overlooking the importance of morning administration to minimize sleep disturbances 4, 5