Is switching from Adderall XR (mixed amphetamine salts) 15 mg to Vyvanse (lisdexamfetamine) 30 mg a safe increase?

Switching from Adderall XR 15 mg to Vyvanse 30 mg: Safety Assessment

Yes, switching from Adderall XR 15 mg to Vyvanse 30 mg is a safe and appropriate dose conversion that represents an equivalent or slightly lower amphetamine exposure. This transition follows standard dose-conversion ratios and is well within established safety parameters for amphetamine-based stimulants 1, 2.

Dose Equivalency Analysis

The conversion from Adderall XR 15 mg to Vyvanse 30 mg represents an approximately equivalent dose, not an increase in amphetamine exposure. The standard conversion ratio is roughly 30 mg Vyvanse ≈ 10 mg Adderall, making 30 mg Vyvanse comparable to 10-15 mg Adderall XR 2. Both medications are amphetamine-based stimulants with similar mechanisms—they inhibit reuptake and promote release of dopamine and norepinephrine 2.

• Vyvanse is a prodrug (lisdexamfetamine) that requires enzymatic conversion in the body to active d-amphetamine, while Adderall XR contains a mixture of amphetamine salts (75% dextroamphetamine and 25% levoamphetamine) that are immediately active 2.
• The prodrug design of Vyvanse provides a smoother pharmacokinetic profile with fewer rapid plasma concentration spikes, potentially offering better tolerability 1.
• Both medications achieve 70-80% response rates in adults with ADHD when properly titrated 1.

Switching Strategy

A direct switch (abrupt transition) is the recommended approach for transitioning between these two amphetamine-based stimulants. No washout period is required because both medications have similar mechanisms and short half-lives 2.

• Stop Adderall XR 15 mg and start Vyvanse 30 mg the next morning 2.
• Both medications should be administered once daily in the morning to minimize insomnia 1, 2.
• Vyvanse provides approximately 12-13 hours of symptom coverage with once-daily dosing, improving medication adherence compared to multiple daily doses 1, 3.

Monitoring During Transition

Close monitoring during the first 1-2 weeks is essential to assess both efficacy and tolerability. Track the following parameters at baseline and during follow-up visits:

• Cardiovascular parameters: Blood pressure and pulse should be measured at baseline and regularly during treatment, as both medications can cause modest increases in heart rate and blood pressure 1, 2, 3.
• Common side effects: Monitor for decreased appetite, insomnia, irritability, headache, upper abdominal pain, and dry mouth—the most frequently reported adverse events with amphetamine stimulants 2, 4.
• ADHD symptom control: Assess symptom improvement throughout the day and watch for rebound symptoms in the afternoon/evening 2.
• Growth parameters: Height and weight should be tracked periodically, particularly in younger patients, though this applies to baseline assessment in adults as well 1, 2.

Safety Considerations

Both medications share the same contraindications and precautions as Schedule II controlled substances with abuse potential. However, Vyvanse's prodrug formulation theoretically confers lower abuse liability compared to immediate-release formulations 1, 2.

• Absolute contraindications: Avoid in patients with uncontrolled hypertension, symptomatic cardiovascular disease, coronary artery disease, tachyarrhythmias, or active substance use disorders 1, 2, 3.
• Drug interactions: Never use with MAO inhibitors due to risk of severe hypertension and potential cerebrovascular accidents; at least 14 days must elapse between discontinuation of an MAOI and initiation of either medication 1.
• Psychiatric monitoring: Screen for emergence or worsening of psychiatric symptoms, including psychosis, mania, or aggression 3.

Titration Flexibility

If 30 mg Vyvanse provides inadequate symptom control after 1-2 weeks, further titration is both safe and appropriate. The FDA-approved dosing for Vyvanse in adults ranges from 30-70 mg daily 1, 3.

• Increase by 10-20 mg increments weekly based on response and tolerability 1.
• Maximum daily dose is 70 mg 1, 3.
• Systematic titration to the lowest effective dose that yields clinical benefit is preferred over strict weight-based dosing 1.

Common Pitfalls to Avoid

• Do not assume this represents a dose increase—the conversion is equivalent or slightly conservative, not an escalation in amphetamine exposure 2.
• Do not delay the switch with unnecessary tapering—direct transition is safe and avoids compliance issues associated with complex dosing schedules 2.
• Do not discontinue monitoring after the initial switch—cardiovascular parameters and symptom control require ongoing assessment throughout treatment 1, 3.
• Do not overlook the potential for improved tolerability—Vyvanse's prodrug mechanism may reduce peak-related side effects compared to immediate-release formulations 1.