Is Amphetamine sold as a single enantiomer or racemic mixture?

Both forms used therapeutically; Adderall is mixed salts, Vyvanse is pure d-amphetamine prodrug

Amphetamine Enantiomers - Chirality in Pharmacology

What happens with Amphetamine enantiomers?

Amphetamine is a CNS Stimulant. The D (R)-enantiomer is Stronger CNS stimulation, focus and attention, while the L (S)-enantiomer is Weaker CNS stimulant, more peripheral effects. D-amphetamine is 3-5x more potent as a CNS stimulant. Adderall uses a 3:1 ratio of d:l salts to optimize efficacy. Vyvanse contains pure d-amphetamine (as a prodrug).

Drug Name	Amphetamine
Drug Class	CNS Stimulant
R-Enantiomer Activity	N/A
S-Enantiomer Activity	N/A
FDA Status	Both forms used therapeutically; Adderall is mixed salts, Vyvanse is pure d-amphetamine prodrug
Year of Discovery	1887
Clinical Significance	D-amphetamine is 3-5x more potent as a CNS stimulant. Adderall uses a 3:1 ratio of d:l salts to optimize efficacy. Vyvanse contains pure d-amphetamine (as a prodrug).

Introduction

Amphetamine is one of the most widely prescribed CNS stimulants, used to treat ADHD and narcolepsy. Its two enantiomers have markedly different potencies in the central nervous system.

Structure Comparison

Both enantiomers share the phenethylamine backbone - a phenyl ring connected through a methylene bridge to an amino group. The key difference is the spatial orientation of the methyl group at the alpha carbon.

Chiral Center

The chiral center is the alpha-carbon bearing four different substituents: the benzyl group, a methyl group, a hydrogen, and the amino group (-NH2).

Pharmacological Differences

D-amphetamine (dextroamphetamine) is 3-5x more potent at releasing dopamine and norepinephrine in the CNS. L-amphetamine has weaker central effects but stronger peripheral (cardiovascular) activity.

Clinical Impact

Adderall uses a carefully tuned 3:1 ratio of d:l amphetamine salts. Vyvanse (lisdexamfetamine) is a prodrug that releases only d-amphetamine, providing smoother pharmacokinetics and lower abuse potential.

Key Takeaway

Amphetamine demonstrates how enantiomers can differ in both potency and tissue selectivity. The d:l ratio is pharmacologically meaningful and directly impacts clinical outcomes.

Visualize R and S enantiomers side by side with activity indicators and pharmacological profiles.

Compare Amphetamine Enantiomers in 3D