Vyvanse Dose Conversion from Adderall XR 30 mg
Start with Vyvanse 50 mg once daily in the morning when switching from Adderall XR 30 mg, as this provides approximately equivalent amphetamine exposure. 1
Conversion Rationale
The conversion from Adderall XR to Vyvanse is not a simple 1:1 ratio—the recommended starting point is Vyvanse 50 mg for patients on Adderall XR 30 mg, though some clinicians use a 1.5:1 to 2:1 conversion ratio. 1 This accounts for the fact that lisdexamfetamine is a prodrug that must be enzymatically converted to active d-amphetamine in the body, primarily through red blood cell metabolism. 2, 3
Administration Guidelines
- Give Vyvanse once daily in the morning to minimize insomnia risk, as the medication provides therapeutic coverage extending up to 13-14 hours post-dose. 2, 4
- No washout period is required when switching between stimulant formulations, as both medications have short half-lives and can be transitioned directly. 5
- The usual starting dose range for lisdexamfetamine is 20-30 mg daily, with weekly titration by 10 mg increments up to a maximum of 70 mg daily. 6
Titration Strategy
- Assess response after 1 week at the initial 50 mg dose before making any adjustments. 5
- If symptom control is inadequate after 1 week, increase by 10 mg weekly increments. 6
- Allow at least 4 weeks at a therapeutic dose before determining treatment failure. 5
- If maximum recommended doses (70 mg) fail to control symptoms adequately, increasing the dose further rarely provides additional benefit—consider switching medication classes instead. 1
Mandatory Monitoring Parameters
- Blood pressure and heart rate should be checked quarterly (minimum) in adults to detect hypertension or tachycardia, as amphetamines increase systolic blood pressure by approximately 2 mmHg, diastolic blood pressure by approximately 2 mmHg, and heart rate by approximately 4 beats per minute. 6, 1
- Weight should be monitored at each visit to assess for appetite suppression, as decreased appetite occurs in up to 47% of patients during initial titration. 1, 4
- Sleep quality and duration should be assessed, as insomnia is a common side effect occurring in up to 27% of patients. 1, 4
- Mood changes, irritability, and anxiety should be monitored, which increase at higher amphetamine doses. 1
Common Pitfalls to Avoid
- Do not dose Vyvanse late in the day, as its 13-14 hour duration of action will cause insomnia if not taken in the morning. 2, 4
- Do not continue escalating doses indefinitely if symptom control remains inadequate—this signals the need for a different therapeutic approach, as approximately 90% of patients respond when both amphetamine and methylphenidate classes are tried. 1
- The most common treatment-emergent adverse events include dry mouth, headache, insomnia, decreased appetite, and irritability, which are typically mild to moderate in severity and consistent with long-acting stimulant use. 2, 7, 3