Is it safe to add Adderall (amphetamine and dextroamphetamine) 20mg twice a day to a treatment regimen that already includes Vyvanse (lisdexamfetamine)?

Concurrent Use of Adderall and Vyvanse

Adding Adderall 20mg BID to a treatment regimen that already includes Vyvanse is not recommended due to the high risk of additive stimulant effects and potential for serious cardiovascular complications.

Rationale for Not Combining These Medications

Both Adderall (mixed amphetamine salts) and Vyvanse (lisdexamfetamine) are amphetamine-based stimulant medications used for ADHD treatment. Combining them presents several significant concerns:

1. Pharmacological Overlap: Vyvanse is a prodrug that converts to dextroamphetamine in the body 1. Adderall also contains dextroamphetamine 2. This creates redundant mechanisms of action.

2. Safety Concerns: The American Academy of Child and Adolescent Psychiatry guidelines emphasize careful monitoring of cardiovascular parameters even with single stimulant therapy 3. Combining two amphetamine-based medications would significantly increase risks.

3. Regulatory Considerations: Both medications are Schedule II controlled substances with high abuse potential 3. Concurrent use would raise regulatory concerns and potentially increase risk of misuse.

Appropriate Alternatives

Instead of combining these medications, consider these evidence-based approaches:

Option 1: Optimize Current Stimulant Therapy

• If Vyvanse is providing inadequate symptom control, adjust the dosage before adding another stimulant
• Vyvanse can be titrated up to appropriate therapeutic levels with regular monitoring 3
• Ensure the current medication is being taken as prescribed and at optimal timing

Option 2: Switch Medications

• If Vyvanse is ineffective or causing intolerable side effects, consider switching completely to Adderall rather than adding it
• The American Academy of Child and Adolescent Psychiatry recommends trying a different stimulant medication if the first is ineffective 4

Option 3: Consider Adjunctive Non-Stimulant Options

• For patients who have partial response to stimulants, adding a non-stimulant medication may be more appropriate than a second stimulant
• Options include atomoxetine, guanfacine, or clonidine 3
• Research suggests that combining a stimulant with a non-stimulant may improve treatment adherence 5

Monitoring and Precautions

If any medication changes are made:

• Monitor vital signs, particularly blood pressure and heart rate
• Assess for side effects including appetite changes, sleep disturbances, and mood changes
• Schedule follow-up visits every 3-4 weeks during dose titration and every 3-6 months once stabilized 3
• Limit caffeine intake to less than 300mg per day 3

Important Considerations

• Drug-Drug Interactions: While stimulants generally don't interact with antidepressants 4, combining two stimulants increases the risk of additive side effects
• Cardiovascular Risk: Patients should be assessed for cardiac disease before initiating or changing stimulant treatment 3
• Abuse Potential: Both medications have abuse potential, with Vyvanse potentially having somewhat lower abuse potential due to its prodrug formulation 1

Remember that medication adjustments for ADHD should always be accompanied by appropriate behavioral interventions, including parent training in behavior management and cognitive-behavioral therapy when indicated 3.