Combining Vyvanse 70mg and Adderall 10mg in ADHD Treatment
Direct Answer
Yes, an ADHD patient can combine lisdexamfetamine (Vyvanse) 70mg with mixed amphetamine salts (Adderall) 10mg, as combination stimulant therapy is an established clinical practice for managing breakthrough symptoms or extending duration of coverage, though this represents a high total amphetamine dose that requires careful monitoring. 1
Clinical Rationale for Combination Therapy
Evidence Supporting Combined Stimulant Use
Combination medication with stimulants and non-stimulants has been shown to facilitate treatment adherence and is particularly indicated when dose-limiting adverse effects prevent optimal monotherapy dosing. 2
The main clinical indication for adding a second stimulant dose is to address breakthrough ADHD symptoms in the late afternoon or evening when the primary long-acting formulation wears off. 1
Approximately 70-80% of adults achieve adequate symptom control with properly titrated stimulant monotherapy, but the remaining 20-30% may require augmentation strategies including combination dosing. 1
Total Daily Amphetamine Exposure Assessment
Dose Equivalency Calculation
Lisdexamfetamine 70mg converts to approximately 30-40mg of dextroamphetamine after enzymatic hydrolysis, making the total daily amphetamine exposure from Vyvanse 70mg plus Adderall 10mg roughly equivalent to 40-50mg of mixed amphetamine salts. 3, 4
The maximum recommended total daily dose for amphetamine salts in adults is 50mg, though clinical practice sometimes extends to 60-65mg (approximately 0.9 mg/kg) when lower doses are insufficient and no dose-limiting side effects occur. 1, 5
This combination places the patient at or near the upper limit of recommended amphetamine dosing, requiring documentation that lower doses were inadequate for symptom control. 1
Specific Monitoring Requirements
Cardiovascular Surveillance
Measure blood pressure and pulse at baseline and at every follow-up visit during combination therapy, as amphetamines produce dose-dependent increases in both parameters. 1, 6
Avoid this combination in patients with symptomatic cardiovascular disease, uncontrolled hypertension, or structural cardiac abnormalities. 1
Symptom and Side-Effect Tracking
Monitor specifically for insomnia, decreased appetite, weight loss, irritability, and anxiety—the most common dose-limiting adverse effects of amphetamine therapy. 1, 5
Obtain weekly ADHD rating scale scores during the initial combination phase to assess whether the added Adderall dose provides meaningful symptom improvement beyond Vyvanse monotherapy. 1
Track height and weight at each visit, particularly in younger adults, as chronic high-dose stimulant use can affect growth parameters. 1
Alternative Optimization Strategies
Before Adding a Second Stimulant
Consider whether Vyvanse 70mg represents an optimized dose—some patients may benefit from adjusting the timing of administration or addressing comorbid conditions (anxiety, depression, sleep disorders) that can masquerade as inadequate ADHD control. 1
Evaluate whether breakthrough symptoms occur at predictable times; if symptoms emerge only in late evening, a smaller afternoon dose of immediate-release amphetamine (5mg rather than 10mg) may suffice. 1
Non-Stimulant Augmentation Options
Extended-release guanfacine (1-4mg daily) is FDA-approved as adjunctive therapy to stimulants for residual ADHD symptoms and may be preferable to adding a second stimulant, particularly when sleep disturbances or oppositional symptoms coexist. 1
Atomoxetine (60-100mg daily) provides "around-the-clock" symptom coverage without controlled-substance restrictions and can be combined with stimulants, though it requires 6-12 weeks for full effect. 1
Practical Implementation Protocol
Dosing Schedule
Administer Vyvanse 70mg in the early morning (upon waking) to maximize daytime coverage, and time the Adderall 10mg dose for early afternoon (approximately 12-2 PM) to target late-day symptom breakthrough without causing insomnia. 1
Avoid administering the Adderall dose later than 2-3 PM to minimize sleep disruption, as amphetamines have elimination half-lives of 10-13 hours. 5
Titration and Adjustment
If combining these medications for the first time, consider starting with Adderall 5mg in the afternoon and titrating upward by 5mg weekly based on symptom response and tolerability. 1
Systematic titration to optimal effect is more important than strict mg/kg calculations, with 70% of patients responding optimally when proper titration protocols are followed. 1
Common Pitfalls and Safety Considerations
Absolute Contraindications
Never combine amphetamines with monoamine oxidase inhibitors (MAOIs) or initiate within 14 days of MAOI discontinuation due to risk of hypertensive crisis. 1
Do not use this combination in patients with active psychosis, uncontrolled hyperthyroidism, glaucoma, or a history of stimulant hypersensitivity. 1
Substance Use Considerations
- Exercise heightened caution when prescribing this high-dose amphetamine combination to patients with current or past substance use disorders; consider long-acting formulations exclusively (Vyvanse has lower abuse potential than immediate-release Adderall) and implement monthly urine drug screening. 1
Tolerance and Dose Escalation
There is little evidence of tolerance development to the therapeutic effects of stimulants on ADHD symptoms when properly dosed; if symptom control deteriorates, assess for medication adherence, emerging comorbidities, or psychosocial stressors before increasing the dose further. 1
If the maximum recommended dose does not provide adequate symptom control, more medication is not necessarily better—consider switching stimulant classes (to methylphenidate), adding a non-stimulant, or intensifying behavioral interventions. 1
Evidence Quality and Limitations
The evidence supporting combination stimulant therapy comes primarily from observational studies and clinical experience rather than randomized controlled trials specifically designed to evaluate dual-stimulant regimens. 2
Most efficacy data for amphetamines derive from monotherapy trials with mean study durations of 5.3 weeks, limiting conclusions about long-term safety and effectiveness of high-dose combination therapy. 6
Lisdexamfetamine has demonstrated efficacy at 14 hours post-dose in adults, which may reduce the need for supplemental afternoon dosing in some patients. 4