What is the difference between Adderall (amphetamine and dextroamphetamine) and dextroamphetamine?

Difference Between Adderall and Dextroamphetamine

Adderall differs from dextroamphetamine primarily in its composition: Adderall contains a 3:1 mixture of dextroamphetamine (d-isomer) and levoamphetamine (l-isomer), while dextroamphetamine contains only the d-isomer, making Adderall potentially more effective for ADHD symptoms due to its mixed amphetamine salt formulation. 1

Composition and Chemical Structure

• Dextroamphetamine: Contains only the dextro (d) isomer of amphetamine, chemically known as d-alpha-methylphenethylamine 2
• Adderall: Contains a 3:1 ratio of dextroamphetamine to levoamphetamine (mixed amphetamine salts) 1, 3

Pharmacological Effects and Efficacy

• Both medications stimulate the release of norepinephrine affecting α- and β-adrenergic receptor sites 4

• The addition of levoamphetamine in Adderall may provide:

  • More robust effects in the morning compared to dextroamphetamine alone 5
  • Different duration of action profile compared to pure dextroamphetamine
  • Potentially broader symptom coverage due to the mixed isomer composition

• In comparative studies, dextroamphetamine Spansules (extended-release) showed:

  • Less robust effects in the morning compared to Adderall
  • Longer duration of action (3-6 hours longer depending on the measure) 5

Clinical Applications

The American Academy of Child and Adolescent Psychiatry recommends both medications for ADHD treatment 6:

• Starting doses:

  • Amphetamine/Adderall: 5-10 mg daily
  • Maximum daily dose: up to 50 mg daily

• For patients who don't respond to one formulation, switching to the other may be beneficial, as approximately 30% of patients may respond differently to various stimulant formulations 6

Duration of Action

• Immediate-release formulations of both medications typically last 4-6 hours
• Extended-release formulations:
  • Adderall XR provides approximately 12 hours of coverage through a dual-release mechanism 3
  • Dextroamphetamine Spansules may provide longer sustained effects on certain measures compared to immediate-release formulations 5

Detection and Testing

• Adderall can be distinguished from pure dextroamphetamine in drug testing by the presence of the l-enantiomer 1
• The proportion of l-enantiomer increases over time as the d-enantiomer is metabolized more rapidly 1

Side Effects and Safety Considerations

Both medications share similar side effect profiles including:

• Cardiovascular effects (tachycardia, increased blood pressure)

• Decreased appetite

• Sleep disturbances

• Potential for abuse (both are DEA Schedule II controlled substances) 4

• Long-term use of either medication has been associated with adverse cardiovascular effects, including potential cardiomyopathy 7

• Regular monitoring of vital signs, growth parameters, and cardiovascular function is recommended with both medications 6

Clinical Decision Making

When choosing between these medications:

1. Consider starting with Adderall if broader symptom coverage is needed due to its mixed isomer composition
2. Consider dextroamphetamine if a patient experiences side effects with Adderall that might be attributed to the levoamphetamine component
3. Extended-release formulations of either medication may be preferred for once-daily dosing and improved adherence
4. Individual response varies, so medication selection should be based on symptom control and tolerability

Common Pitfalls

• Failing to recognize that a patient not responding to one formulation may respond to the other
• Not monitoring for cardiovascular side effects with long-term use of either medication
• Overlooking the potential for abuse and diversion with both medications
• Assuming identical efficacy and side effect profiles despite their different compositions