What is the recommended dosing strategy when switching a patient from Adderall XR (amphetamine/dextroamphetamine) 30 mg to Vyvanse (lisdexamfetamine)?

Switching from Adderall XR 30 mg to Vyvanse

When switching from Adderall XR 30 mg to Vyvanse, start with Vyvanse 50 mg once daily in the morning, as this provides approximately equivalent amphetamine exposure. 1

Conversion Rationale

• Lisdexamfetamine (Vyvanse) is a prodrug that is therapeutically inactive until enzymatically converted in the blood to dextroamphetamine and L-lysine 2, 3
• The conversion from Adderall XR to Vyvanse is not a simple 1:1 ratio—a reasonable 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
• Vyvanse follows linear pharmacokinetics at therapeutic doses (30-70 mg), with the prodrug design resulting in delayed absorption compared to immediate-release amphetamine formulations 3

Switching Protocol

• Direct switch without washout period: You can switch directly from Adderall XR to Vyvanse on the same day, as both are amphetamine-based stimulants with similar mechanisms of action 1, 4
• Starting dose: Begin with Vyvanse 50 mg once daily in the morning 1, 4
• Timing: Administer in the morning with or without food; avoid afternoon doses to prevent insomnia 4
• Titration if needed: If symptom control is inadequate after one week, increase by 10-20 mg increments at approximately weekly intervals, up to a maximum of 70 mg daily 1, 4

Administration Options

Vyvanse can be taken in multiple ways if swallowing capsules is difficult: 4

• Swallow the capsule whole, OR
• Open the capsule and mix the entire contents with yogurt, water, or orange juice—consume immediately and do not store 4
• Do not divide a single dose; take the full capsule amount 4

Mandatory Monitoring Parameters

Monitor the following at each visit (quarterly minimum in adults): 5

• Blood pressure and heart rate to detect hypertension or tachycardia—amphetamines increase systolic blood pressure by approximately 2 mmHg and diastolic blood pressure by approximately 2 mmHg, with heart rate increases of approximately 4 beats per minute 6
• Weight to assess for appetite suppression and nutritional adequacy 5
• Sleep quality and duration, as stimulants commonly cause insomnia when dosed too late in the day 5, 4
• Mood changes, irritability, and anxiety, which increase at higher amphetamine doses 5

Expected Duration of Effect

• Vyvanse provides efficacy for a full treatment day, up through and including 6 PM, based on clinical trials 3
• Lisdexamfetamine has demonstrated efficacy at 14 hours post-dose in adults, making it suitable for managing ADHD symptoms that extend late into the day 7

Common Pitfalls to Avoid

• Do not dose after morning hours—afternoon or evening dosing is the most common cause of treatment-related insomnia 4
• Do not continue escalating doses indefinitely if symptom control remains inadequate at maximum doses (70 mg)—this signals the need for a different therapeutic approach, such as switching to methylphenidate-based stimulants or adding non-stimulant medications 5
• Do not overlook cardiovascular screening—assess for cardiac disease history, family history of sudden death or ventricular arrhythmia, and perform a physical exam before initiating treatment 4
• Do not ignore withdrawal risk—while switching between amphetamine formulations typically does not require tapering, be aware that amphetamines are DEA Schedule II controlled substances with high potential for abuse 4, 8

Expected Adverse Effects

The most common adverse events with Vyvanse are typical of amphetamine products: 3

• Decreased appetite
• Insomnia
• Upper abdominal pain
• Headache
• Irritability
• Weight loss
• Nausea

When to Consider Alternative Approaches

• If maximum recommended doses (70 mg) fail to control symptoms adequately, increasing the dose further rarely provides additional benefit 5
• Approximately 90% of patients respond when both amphetamine and methylphenidate classes are tried, so consider switching medication classes if Vyvanse is ineffective 5
• Participants taking amphetamines are 2.69 times more likely to withdraw from treatment due to adverse effects compared to placebo, with an absolute risk increase of 4.3% 6