Amphetamine

Stimulant (dopamine-norepinephrine reuptake inhibitor and releaser; serotonin reuptake inhibition)

Dosing

Dextroamphetamine

Dextro is the more potent of the amphetamine isomers (2-4 times more potent than levo).

FORMS: Dextroamphetamine (4-6 hr, max 40 mg), Spansules (6-10 hr, max 40 mg), Vyvanse-prodrug (12-14 hr, max 70 mg, target for binge eating = 50-70 mg)

To convert from another stimulant to dextroamphetamine multiply by number in parentheses: Adderall (0.8), Evekeo (0.75), Methylphenidate (0.4), Dexmethylphenidate (0.8). To convert to Vyvanse, multiply by: Dextroamphetamine (2.5), Adderall (2.0), Evekeo (1.5), Methylphenidate (1.0), Dexmethylphenidate (2.0).

Vyvanse is FDA approved in binge eating disorder but avoid if has bipolar, psychosis, borderline, or other complex comorbidities.

Amphetamine 3:1

These formulations have a higher ratio of dextro (3:1).

FORMS: Adderall (4-6 hr, max 40 mg), Adderall XR (10-12 hr, max 40 mg), Mydayis $ (14-16 hr, max 50 mg), Adzenys XR-ODT or Liquid $ (10-12 hr, max 18.2 mg), Dyanavel-XR Liquid $ (12 hr, max 20 mg).

To convert from another stimulant to Adderall/Mydayis, multiply by number in parentheses: Evekeo (0.75), Dextroamphetamine (1.2), Vyvanse (0.5), Methylphenidate (0.5), Dexmethylphenidate (1.0). To convert from Adzenys to other 3:1 amphetamine salts multiply Adzenys x1.6.

With Adderall XR, blood concentrations are lowered if taken with a large fatty meal.       

Amphetamine 1:1

These formulations are less desirable as they have more of the isomer that causes side effects (levo).

FORMS: Instant release and ODT (eg, Evekeo, 9-10 hr, max 50 mg)

To convert from another stimulant multiply by number in parentheses: Adderall (1.3), Dextroamphetamine (1.5), Vyvanse (0.6), Methylphenidate (0.6), Dexmethylphenidate (1.3).

Management

Vyvanse is preferred form (abuse deterrent, steadier serum levels). Amphetamines have a higher risk of abuse, neurotoxicity, mania, psychosis than methylphenidates. Use lower dose in elderly (> 65, eg Adderall 10-20 mg).

EMR Text