Pharm

Dextroamphetamine

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Dextroamphetamine, Dexedrine, Dextrostat, Adderall, Lisdexamfetamine, Vyvanse

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Indications

Attention Deficit Hyperactivity Disorder (ADHD)

Contraindications

Congenital Heart Defect (ask related PMH, Family History and screen on ADHD exam)
1. Consider an EKG before prescribing
2. Vetter (2008) Circulation 117(18):2407-23. [PubMed]

Precautions

See ADHD Medication for overall approach and medication selection
Maximum Dosing
1. Adults and older adolescents (>50 kg) may in some cases need dosing in excess of listed maximum
2. Exercise caution and Informed Consent as these doses are not FDA approved
  1. Doses exceed the manufacturers recommendation
3. Absolute maximum dose of mixed Amphetamine salts: 60 mg per day
4. References
  1. (2013) Presc Lett 20(9): 50-1

Pharmacokinetics

Immediate Release Dextroamphetamine (Dexedrine, Dextrostat)
1. Onset of activity: 20 to 60 minutes
2. Peak effect: 1 to 2 hours
3. Duration of activity: 4 to 6 hours
Extended Release Dextroamphetamine (Dexedrine Spansules)
1. Onset of activity: 60 to 90 minutes
2. Duration of activity: 8 hours
Amphetamine-Dextroamphetamine (Adderall)
1. Onset of activity: 30 to 60 minutes
2. Peak effect: 1 to 2 hours
3. Duration of activity: 6-8 hours
Adderall XR Capsules
1. Duration of activity: 10-12 hours
2. Biphasic release (similar to Ritalin LA)
  1. Immediate release beads: 50%
  2. Delayed release beads: 50% (starts 4 hours later)
3. High fat breakfast alters absorption

Dosing
Immediate Release Dextroamphetamine (Dexedrine, Dextrostat)

Range: 0.15 to 0.5 mg/kg/day
Maximum: 40 mg/day
Frequency: Lasts 4 hours (dose up to three times daily)
Start: 2.5 mg orally qAM and/or noon
Typical Dose: 5-15 mg orally twice daily or 5-10 mg orally three times daily

Dosing
Intermediate Release Dextroamphetamine (Dexedrine Spansules)

Range: 0.3 to 0.8 mg/kg/dose
Maximum: 40 mg/day
Start: 5 mg orally once or twice daily
Typical Dose: 5-30 mg orally once daily or 5-15 mg orally twice daily

Dosing
Intermediate Release Amphetamine-Dextroamphetamine (Adderall)

Very similar to Extended Release Dextroamphetamine (Dexedrine Spansules)
Range: 0.15 to 0.5 mg/dose
Maximum: 40 mg/day
Start: 2.5 to 5 mg orally once to twice daily
Typical Dose: 5-30 mg orally once daily or 5-15 mg orally twice daily

Dosing
Extended Release Amphetamine-Dextroamphetamine (Adderall XR)

Initial: 10 mg orally once daily
Typical dose: 10-30 mg orally once daily
Maximum: 30 mg/day

Preparation
Lisdexamfetamine (Vyvanse)

Dextroamphetamine is a D-Amphetamine prodrug, metabolized to the active form
Inactive until cleaved in GI Tract
1. Decreased abuse potential when injected or snorted
2. Decreased "buzz" when swallowed
Indicated for ADHD in ages 6-12 years
Dosing: Start with lowest effective dose
1. Medication doses range from 30 mg to 70 mg qAM

Management Difficulty Swallowing Medication - Long Acting Amphetamines

Generic
1. Adderall XR (may be sprinkled on apple sauce)
Expensive
1. Adzenys XR Orally Disolving Tablet 6.3 mg (lasts 12 hours)
2. Dynavel XR Suspension 2.5 mg/ml (lasts 12 hours)
References
1. (2016) Presc Lett 23(3):16

Adverse Effects

See ADHD Medication

Safety

Pregnancy Category C
Avoid in Lactation

References