Transitioning from Adderall XR to IR: Recommended Dosing Strategy
When converting from Adderall XR to IR, use the same total daily dose but divide it into 2-3 doses given 4-6 hours apart, with the first dose upon awakening. 1
Conversion Algorithm
Step 1: Calculate Total Daily Dose
- Identify the current total daily dose of Adderall XR (e.g., 30 mg XR once daily = 30 mg total daily dose) 2, 3
- This total daily dose remains unchanged when converting to IR formulation 1
Step 2: Divide Into Multiple Daily Doses
- Split the total daily dose into 2-3 divided doses given at 4-6 hour intervals 1
- For example: 30 mg XR daily converts to either:
- 15 mg IR twice daily (morning and midday), OR
- 10 mg IR three times daily (morning, midday, and afternoon) 1
Step 3: Timing Considerations
- Give the first dose immediately upon awakening 1
- Space subsequent doses 4-6 hours apart 1
- Avoid late evening doses to prevent insomnia 1
- The last dose should typically be given no later than early afternoon to minimize sleep disturbances 3, 4
Pharmacokinetic Rationale
The conversion maintains equivalent total daily exposure because:
- Adderall XR provides approximately 12 hours of coverage through its dual-release mechanism (50% immediate-release, 50% delayed-release at 4 hours) 5, 6
- Adderall IR has a duration of action of approximately 4 hours, necessitating multiple daily doses to achieve similar symptom control throughout the day 7, 6
- The bioavailability is comparable between formulations when total daily doses are equivalent 6
Monitoring After Conversion
Initial Assessment (First 1-2 Weeks)
- Evaluate symptom control throughout the entire day, particularly during late afternoon/evening when IR coverage may wane 3, 4
- Monitor for rebound symptoms between doses, which may indicate need for dose timing adjustment 8
- Assess for sleep disturbances, as improper timing of the last IR dose is a common pitfall 3, 4
Ongoing Monitoring
- Check blood pressure and pulse quarterly in adults 2, 4
- Assess efficacy using standardized ADHD rating scales when possible 4
- Monitor weight at each visit to detect appetite suppression 3
Common Pitfalls to Avoid
- Failing to account for the shorter duration of IR formulation: Patients may experience symptom breakthrough in late afternoon/evening if only dosed twice daily 7, 6
- Dosing too late in the day: The last IR dose should be given by early afternoon to prevent insomnia 1
- Not allowing adequate time between doses: Maintain 4-6 hour intervals to optimize coverage 1
- Assuming the conversion will provide identical symptom control: Some patients may require minor dose adjustments after conversion due to individual pharmacokinetic variability 8
When Dose Adjustment May Be Needed
If symptom control is inadequate after conversion:
- First optimize the timing and distribution of IR doses before increasing total daily dose 1
- Consider switching to three times daily dosing if twice daily dosing leaves gaps in coverage 1
- If adjustments are needed, increase in 5 mg increments weekly based on response and tolerability 2, 3
- Maximum recommended daily dose remains 50 mg regardless of formulation 2