Switching from Adderall 10mg IR to XR
When switching from Adderall 10mg IR to Adderall XR, start with 10mg XR once daily in the morning. 1, 2
Conversion Rationale
The conversion is straightforward because 10mg XR is the standard starting dose for Adderall XR and provides equivalent total daily amphetamine exposure to the immediate-release formulation through its unique two-phase delivery system. 1, 2
Key Pharmacokinetic Considerations
Adderall XR releases medication in two phases: 50% immediately upon ingestion and 50% approximately 4 hours later, providing 12-hour symptom coverage with a single morning dose. 3, 4
The bioavailability of Adderall XR 20mg is comparable to Adderall IR 10mg twice daily, establishing the dose equivalence pattern. 3
Time to peak concentration (Tmax) is delayed by approximately 3 hours with XR compared to IR formulation, but therapeutic effects begin within 1.5 hours. 3, 4
Practical Switching Protocol
Discontinue the IR formulation and initiate 10mg XR the following morning. 1, 2
Administer once daily in the morning to minimize sleep disturbances. 1, 2
Allow at least one week at the new dose before considering any adjustment to properly evaluate therapeutic response. 1, 2
Titrate in 5mg weekly increments if symptom control is inadequate, up to a maximum of 50mg daily. 1, 5, 2
Monitoring After Conversion
Assess blood pressure and pulse at the first follow-up visit after switching. 1, 2
Evaluate symptom control throughout the day, particularly in afternoon and late afternoon periods, as XR provides extended coverage compared to a single IR dose. 6
Monitor for appetite suppression by weighing the patient at each visit. 1, 2
Screen for side effects including insomnia, anorexia, headaches, and social withdrawal. 1
Common Pitfalls to Avoid
Do not start at a higher XR dose (such as 20mg) simply because the patient was taking 10mg IR—this would represent dose escalation, not conversion, and increases unnecessary side effects. 1, 2
Do not split or crush XR capsules, as this destroys the extended-release mechanism and can cause dangerous immediate release of the full dose. 5
Do not overlook food effects: High-fat meals significantly reduce early amphetamine exposure from XR formulations, potentially causing inconsistent symptom control compared to fasted states. 7
Do not increase doses more frequently than weekly, as insufficient time between adjustments prevents accurate assessment of therapeutic response. 1, 2
Do not exceed 50mg daily—if maximum dose fails to provide adequate control, switch to an alternative medication rather than exceeding recommended limits. 1, 5, 2