Taking Vyvanse 30mg and Adderall 20mg Together is NOT Safe
You should not take lisdexamfetamine (Vyvanse) 30 mg and mixed amphetamine salts (Adderall) 20 mg together on the same day. This combination represents excessive amphetamine dosing that significantly increases risks of serious cardiovascular events, psychiatric complications, and overdose.
Why This Combination is Dangerous
Both medications are amphetamine-based stimulants that work through identical mechanisms—they both increase dopamine and norepinephrine by blocking reuptake and promoting release of these neurotransmitters 1. Vyvanse is a prodrug that converts to d-amphetamine in the blood, while Adderall contains mixed amphetamine salts. Taking both simultaneously creates a cumulative amphetamine load of approximately 42-50 mg of active amphetamine equivalents, which exceeds standard maximum dosing recommendations.
Specific Safety Concerns
Cardiovascular Risks
The FDA labeling for Vyvanse explicitly warns about risks in patients with serious heart disease, including sudden death in those with cardiac abnormalities 1. Combining these medications compounds the following risks:
- Severe hypertension and tachycardia from additive sympathomimetic effects
- Increased risk of myocardial infarction, stroke, or sudden cardiac death
- Vasospasm and potential aortic dissection 1
Psychiatric Complications
Stimulant overdose characteristically produces 1:
- Psychomotor agitation, confusion, and hallucinations
- New or worsening psychotic symptoms
- Serotonin syndrome (especially if taking other serotonergic medications)
- Severe anxiety and panic
Overdose Risk
The FDA explicitly states that misuse of amphetamine medications "can lead to overdose and death" and that "the risk of overdose and death is increased with higher doses" 1. Combining two amphetamine products creates exactly this scenario.
What the Guidelines Say
The 2002 AACAP practice parameters emphasize that stimulant medications have specific contraindications and require careful monitoring 2. While guidelines discuss using stimulants in ADHD treatment, there is no clinical indication or guideline support for combining two different amphetamine products simultaneously. The Asian guidelines specify maximum daily doses (e.g., 70 mg for lisdexamfetamine, 60 mg for methylphenidate formulations) but these refer to single-agent therapy 3.
Clinical Context
Research demonstrates that both Vyvanse and Adderall are effective as monotherapy 4, 5, 6, 7. Studies comparing these medications show they work through the same mechanisms and have similar efficacy profiles 4, 6. There is no evidence supporting combination therapy with two amphetamine products, and doing so violates basic pharmacological principles of avoiding duplicate therapy with identical mechanisms.
What You Should Do Instead
If your current ADHD medication isn't adequately controlling symptoms:
- Optimize the dose of your current single medication up to the maximum recommended dose (70 mg/day for Vyvanse or 60 mg/day for Adderall) 3, 1
- Switch from one stimulant to another if the current one is ineffective
- Consider adding a non-stimulant medication like atomoxetine or guanfacine as adjunctive therapy
- Discuss with your prescriber whether you need medication adjustment, not medication stacking
Critical Pitfall to Avoid
Never combine two stimulant medications with the same active ingredient or mechanism without explicit direction from a physician who understands you're taking both. The cumulative amphetamine exposure creates serious health risks that far outweigh any potential benefit.