Taking Vyvanse and Adderall Together: Safety Assessment
No, it is not safe to take Vyvanse and Adderall together—both are amphetamine-based stimulants that work through identical mechanisms, and combining them creates excessive amphetamine exposure with significantly increased cardiovascular risks and no therapeutic benefit. 1
Why This Combination Is Dangerous
Both medications are amphetamine-based stimulants that inhibit reuptake and promote release of dopamine and norepinephrine through the same mechanism. 1 The key difference is that Vyvanse is a prodrug requiring conversion to active d-amphetamine in the body, while Adderall contains immediately active amphetamine salts (75% dextroamphetamine and 25% levoamphetamine). 1 Taking both simultaneously is essentially doubling up on the same medication class, creating an overdose scenario rather than complementary therapy.
Cardiovascular Risks of Excessive Amphetamine Exposure
- Stimulant medications cause small but statistically significant increases in blood pressure and heart rate at therapeutic doses. 2
- Amphetamine overdose causes hyperactivity, hyperthermia, tachycardia, tachypnea, mydriasis, tremors, and seizures. 3
- α-Adrenergic stimulation causes vasoconstriction and increased total peripheral resistance, while β-adrenergic receptor stimulation leads to increased heart rate and stroke volume. 3
- Adults with ADHD taking stimulants are at risk for rare but serious cardiovascular events including acute myocardial infarction, arrhythmia, and cardiomyopathy. 4
- Both medications should be avoided in patients with uncontrolled hypertension, coronary artery disease, tachyarrhythmias, or active substance use disorders. 1
The Correct Approach: Switching, Not Combining
If Vyvanse is not providing adequate symptom control, the appropriate strategy is a direct switch to Adderall, not adding it on top. 1
Switching Protocol
- Stop Vyvanse and start Adderall the next day at an equivalent dose with no washout period required because both have similar mechanisms and short half-lives. 1
- Approximate dose conversions: 30 mg Vyvanse ≈ 10 mg Adderall; 50 mg Vyvanse ≈ 15-20 mg Adderall; 70 mg Vyvanse ≈ 20-30 mg Adderall. 1
- For Adderall IR: Start with 5-10 mg once or twice daily (morning and midday), titrate in 5-10 mg increments weekly as needed. 1
- For Adderall XR: Start with 10-20 mg once daily in the morning, titrate in 5-10 mg increments weekly up to maximum 50 mg daily. 1
Monitoring During Transition
- Monitor closely during the first 1-2 weeks for decreased appetite, insomnia, irritability, headache, upper abdominal pain, and cardiovascular effects such as blood pressure and heart rate changes. 1
- Assess ADHD symptom improvement throughout the day and watch for rebound symptoms, particularly with shorter-acting formulations. 1
Common Pitfalls to Avoid
- Never combine two amphetamine-based stimulants—this is not standard practice and represents a medication error, not optimization. 1
- Do not assume that combining stimulants will provide better coverage than properly titrating a single agent to optimal dose. 5
- Avoid using stimulants in patients with personal or family history of cardiovascular disease without careful cardiovascular assessment. 2
- Both are Schedule II controlled substances with abuse potential, though Vyvanse's prodrug formulation theoretically confers lower abuse liability. 1, 6
Alternative Strategies for Inadequate Response
If a single stimulant at optimal doses is not providing adequate symptom control:
- Consider switching to methylphenidate-based medications (Ritalin, Concerta) as they have different mechanisms and side effect profiles. 1
- Approximately 40% of patients respond to both amphetamine and methylphenidate classes, while 40% respond to only one. 5
- Consider adding adjunctive non-stimulant medications like guanfacine extended-release for residual symptoms rather than adding a second stimulant. 5
- Evaluate for comorbid conditions (depression, anxiety) that may require separate treatment with SSRIs or other agents. 5