Is Dexedrine a Mixed Amphetamine Salt?
No, Dexedrine is not a mixed amphetamine salt but rather contains only dextroamphetamine sulfate, which is the dextro isomer of amphetamine. 1
Comparison of Dexedrine vs. Mixed Amphetamine Salts
Dexedrine (Dextroamphetamine)
- Dexedrine contains only dextroamphetamine sulfate, which is the d-isomer (dextro isomer) of amphetamine 1
- Chemically, dextroamphetamine is d-alpha-methylphenethylamine, present as the neutral sulfate 1
- Dexedrine is typically dosed starting at 5 mg twice daily for immediate release or 10 mg once daily for Spansule (extended-release) formulations 2
Mixed Amphetamine Salts (Adderall)
- Adderall contains a 3:1 mixture of d-amphetamine and l-amphetamine enantiomers 3
- Specifically, Adderall contains amphetamine salts including dextroamphetamine sulfate, dextroamphetamine saccharate, amphetamine aspartate, and amphetamine sulfate 3, 4
- The standard starting dose for Adderall XR is 10 mg once daily in the morning 2
Clinical Implications of the Difference
Pharmacological Effects
- The d-isomer (dextroamphetamine in Dexedrine) has more potent central nervous system effects than the l-isomer 3
- The l-isomer present in mixed amphetamine salts contributes more to peripheral effects such as cardiovascular stimulation 5
- Both medications increase blood pressure and heart rate, but the specific profile may differ due to the enantiomer composition 5, 6
Metabolism and Excretion
- The d-enantiomer and l-enantiomer are metabolized at different rates, with the l-enantiomer typically being eliminated more slowly 3
- This difference in metabolism affects the duration of action and excretion profile of the medications 3, 7
Therapeutic Use
- Both medications are used to treat ADHD and narcolepsy, but the single-isomer formulation (Dexedrine) may have a slightly different side effect profile 4, 7
- For pregnancy considerations, both medications carry similar risk profiles, with the American College of Obstetricians and Gynecologists noting that amphetamines generally do not seem to be associated with major congenital malformations 2, 8
Common Pitfalls in Clinical Practice
- Confusing Dexedrine (dextroamphetamine only) with Adderall (mixed amphetamine salts) can lead to inappropriate dosing, as they have different potency profiles 3, 4
- When interpreting drug tests, it's important to note that Dexedrine use will show only the d-enantiomer of amphetamine, while Adderall use will show both d- and l-enantiomers 3
- Switching between these medications requires dose adjustment due to their different compositions and potencies 4, 7