What is the comparison between Vyvanse (lisdexamfetamine) and Adderall (amphetamine/dextroamphetamine) for treating Attention Deficit Hyperactivity Disorder (ADHD)?

Vyvanse vs. Adderall for ADHD Treatment

Vyvanse (lisdexamfetamine) is preferable to Adderall (amphetamine/dextroamphetamine) for ADHD treatment due to its lower abuse potential, longer duration of action, and similar efficacy profile.

Mechanism of Action and Pharmacokinetics

• Vyvanse (lisdexamfetamine):

  • Prodrug that requires enzymatic conversion in the bloodstream to active dextroamphetamine 1
  • Conversion occurs primarily in red blood cells after oral administration 1
  • Slower onset of action (approximately 1 hour for lisdexamfetamine and 3.5-4.4 hours for conversion to dextroamphetamine) 1
  • Longer duration of action with once-daily dosing 2
  • Elimination half-life of dextroamphetamine: 10-11.3 hours in adults 1

• Adderall (amphetamine/dextroamphetamine):

  • Direct-acting stimulant that does not require metabolic conversion
  • More rapid onset of action
  • Shorter duration requiring multiple daily doses (immediate-release formulation)

Abuse Potential

• Vyvanse has significantly lower abuse potential:

  • Cannot be easily converted to an abusable form when injected or snorted 3
  • The prodrug formulation requires enzymatic conversion in the bloodstream, making it difficult to manipulate 3
  • Recommended for adolescents at risk for stimulant misuse or diversion 3
  • Specifically noted by the American Academy of Pediatrics as having less abuse potential 3

• Adderall has higher abuse potential:

  • More easily misused via alternative routes of administration
  • More likely to produce rapid euphoric effects
  • Higher risk for diversion, particularly among adolescents 3

Efficacy

• Both medications are effective for ADHD symptom management
• A head-to-head study showed Vyvanse produced a faster and more robust treatment response compared to non-stimulant atomoxetine in patients who previously responded inadequately to methylphenidate 4
• Vyvanse has demonstrated effectiveness in treatment-naïve patients and those who did not respond satisfactorily to previous ADHD therapies, including methylphenidate 2

Special Considerations

Adolescents

• Vyvanse is specifically recommended for adolescents due to:
  • Lower abuse potential 3
  • Longer duration of action providing coverage during driving 3
  • Once-daily dosing improving adherence 2

Patients with Substance Use Disorder

• Vyvanse may be appropriate for patients with stimulant use disorder:
  • Case reports show successful treatment of ADHD without exacerbating addiction 5
  • May actually reduce cravings for illicit stimulants 5
  • Atomoxetine should be considered first-line instead of stimulants in patients with substance use disorders 6

Side Effects and Safety

• Both medications have similar side effect profiles typical of stimulants:

  • Increased blood pressure and heart rate
  • Decreased appetite and weight loss
  • Sleep disturbances
  • Anxiety

• Vyvanse and immediate-release dextroamphetamine produced similar peak increases in cardiovascular parameters and adverse effects in direct comparison 7

Practical Considerations

• Dosing convenience:

  • Vyvanse: Once-daily dosing 2
  • Adderall: Multiple daily doses may be required (immediate-release)

• Duration of coverage:

  • Vyvanse provides longer symptom control throughout the day 2
  • Particularly beneficial for driving safety in adolescents 3

Common Pitfalls and Caveats

1. Misunderstanding abuse potential: While Vyvanse has lower abuse potential when snorted or injected, a study showed similar abuse-related subjective effects when both medications are taken orally 7

2. Delayed onset: Prescribers should be aware that Vyvanse takes longer to reach peak effect (approximately 1 hour longer than immediate-release dextroamphetamine) 7

3. Cost considerations: Vyvanse is brand-name only, while generic versions of Adderall are available

4. Food interactions: Food prolongs the time to peak concentration of Vyvanse by approximately 1 hour but does not affect overall exposure 1

5. Monitoring requirements: Both medications require regular monitoring of blood pressure, heart rate, growth parameters, and potential psychiatric side effects