What is the Adderall XR (mixed amphetamine salts) dose equivalent to 30 mg of Vyvanse (lisdexamfetamine)?

Vyvanse 30 mg to Adderall XR Dose Equivalence

Vyvanse 30 mg is approximately equivalent to Adderall XR 10 mg based on the active amphetamine content, as Vyvanse 30 mg delivers roughly 8.9 mg of dextroamphetamine after conversion from the prodrug lisdexamfetamine. 1

Pharmacological Basis for Conversion

The conversion is based on the molecular pharmacology of these medications:

• Vyvanse 30 mg contains 30 mg of lisdexamfetamine dimesylate, which is equivalent to 17.3 mg of lisdexamfetamine base 1
• Lisdexamfetamine is a prodrug that is converted to dextroamphetamine through hydrolysis primarily by red blood cells after oral administration 1
• The conversion is not 1:1 by weight due to the lysine molecule attached to the amphetamine

Adderall XR contains mixed amphetamine salts (75% dextroamphetamine and 25% levoamphetamine), so the dextroamphetamine content is approximately 75% of the total dose.

Clinical Equivalence Considerations

Key Differences Beyond Dose:

• Duration of action: Both are extended-release formulations, but Vyvanse has a smoother, more consistent release profile due to its prodrug mechanism 1
• Peak effect timing: Vyvanse reaches peak dextroamphetamine levels at approximately 3.5-4 hours post-dose, while Adderall XR has a biphasic release 1
• Abuse potential: Vyvanse has lower abuse potential because the prodrug must be metabolized to become active 1

Clinical Trial Evidence:

A head-to-head comparison study demonstrated that Vyvanse 30 mg, 50 mg, and 70 mg all showed significant efficacy compared to placebo, with mixed amphetamine salts XR included as a reference arm 2. The study confirmed both medications effectively reduce ADHD symptoms, though direct dose equivalence was not the primary endpoint.

Practical Conversion Approach

When switching between these medications:

1. Start with Adderall XR 10 mg when converting from Vyvanse 30 mg as the initial equivalent dose
2. Titrate based on clinical response within 7 days, as stimulant effects are seen rapidly 3
3. Monitor for both efficacy and tolerability, as individual response is variable and unpredictable 3
4. Do not calculate doses based on mg/kg, as variations in dose have not been found related to height or weight 3

Important Caveats:

• Individual response varies significantly between methylphenidate and amphetamine classes, and even within the amphetamine class between different formulations 3
• More than 90% of patients respond to one psychostimulant if a range of medications from both classes are tried 3
• The conversion ratio is an approximation; clinical titration remains essential 4
• Cardiovascular monitoring is mandatory: amphetamines increase systolic blood pressure by approximately 1.93 mmHg and heart rate by 3.71 bpm 5

Monitoring Requirements:

• Assess response within 7 days of dose adjustment 3
• Monitor blood pressure and heart rate at each visit
• Evaluate for adverse effects including decreased appetite, sleep disturbances, and mood changes 4
• Withdrawal due to adverse effects is 2.69 times more likely with amphetamines than placebo 5

The 3:1 ratio (Vyvanse 30 mg ≈ Adderall XR 10 mg) serves as a reasonable starting point, but expect to adjust based on individual patient response, tolerability, and duration of symptom control needed throughout the day.