What Vyvanse (lisdexamfetamine) dose is equivalent to 30 mg of Adderall (mixed amphetamine salts) for an adult patient with ADHD?

Vyvanse Dose Equivalent to 30 mg Adderall

For an adult patient taking 30 mg of Adderall, the equivalent Vyvanse (lisdexamfetamine) dose is 50–70 mg once daily in the morning.

Conversion Rationale

The conversion from Adderall to Vyvanse is not a simple 1:1 ratio because lisdexamfetamine is a prodrug that must be enzymatically converted to d-amphetamine in red blood cells, whereas Adderall contains both immediate-release d-amphetamine and l-amphetamine salts 1, 2.

The general conversion approach is approximately 1.5:2.3 ratio (Adderall to Vyvanse), meaning:

• 30 mg Adderall ≈ 50–70 mg Vyvanse 1, 3

Most clinical guidelines and studies position 50–70 mg as the typical maintenance dose range for Vyvanse in adults, which corresponds to moderate-to-high therapeutic dosing of mixed amphetamine salts 3, 2.

Starting and Titration Protocol

When switching from Adderall 30 mg to Vyvanse:

• Start at Vyvanse 50 mg once daily in the morning 3
• If symptom control is inadequate after 1 week, increase to 60 mg, then 70 mg (maximum approved dose) 3
• Titrate by 10 mg weekly based on clinical response and tolerability 3
• The therapeutic range for Vyvanse is 30–70 mg daily, with 50–70 mg representing the most common maintenance doses 3

Key Differences Between Adderall and Vyvanse

Duration of action:

• Adderall (immediate-release): 4–6 hours; Adderall XR: ~12 hours 4
• Vyvanse: up to 14 hours post-dose, providing extended late-day coverage 2

Pharmacokinetics:

• Vyvanse remains inactive until enzymatic conversion in red blood cells, resulting in a smoother onset and potentially fewer peak-related side effects compared to Adderall 2
• This prodrug mechanism may reduce abuse potential compared to immediate-release amphetamine formulations 1

Monitoring During Transition

Baseline and ongoing assessments:

• Measure blood pressure and pulse before switching and at each follow-up during titration 1, 3
• Obtain ADHD rating scales weekly during the first 2–4 weeks to assess symptom control 3
• Monitor for appetite suppression, insomnia, headache, and weight loss—the most common stimulant side effects 3, 2

Follow-up schedule:

• Weekly contact (by phone or in-person) during initial titration 3
• Monthly visits after dose stabilization to assess efficacy, side effects, and growth parameters 3

Expected Outcomes

• 70–80% of adults with ADHD respond to amphetamine-based stimulants when properly titrated 1, 5
• Vyvanse demonstrates significant ADHD symptom reduction with effect sizes comparable to other amphetamine formulations (SMD -1.06 for lisdexamfetamine) 5
• Symptom improvement typically occurs within the first week of treatment 4

Common Pitfalls to Avoid

• Do not assume a 1:1 conversion—Vyvanse requires higher milligram dosing than Adderall due to its prodrug formulation 1, 2
• Do not start at 30 mg Vyvanse—this is likely subtherapeutic for someone previously on 30 mg Adderall; start at 50 mg 3
• Do not skip cardiovascular monitoring—both medications carry cardiovascular effects that require baseline and ongoing assessment 1, 3
• Do not exceed 70 mg daily—this is the maximum FDA-approved dose for Vyvanse 3

Alternative Consideration

If the patient does not achieve adequate symptom control at Vyvanse 70 mg after 4 weeks, consider switching to methylphenidate-based stimulants, as approximately 40% of patients respond preferentially to one stimulant class over another 1, 5.