What is dextroamphetamine?
Dextroamphetamine is the dextrorotatory, or "right-handed," enantiomer of the amphetamine molecule. Amphetamine itself is a synthetic, non-catecholamine, sympathomimetic amine, and a powerful central nervous system (CNS) stimulant. Dextroamphetamine is considered more potent than levoamphetamine, the other isomer of amphetamine, and is primarily responsible for the central nervous system effects of amphetamine-based medications. It is available as a single-ingredient medication (such as the brand name Dexedrine) and is also a component of mixed amphetamine salts (like Adderall).
Mechanism of action
This medication works by affecting neurotransmitters in the brain, specifically norepinephrine and dopamine. Its primary mechanism involves facilitating the release of these catecholamines from nerve terminals and inhibiting their reuptake into presynaptic neurons. This leads to an increase in the concentration of dopamine and norepinephrine in the synaptic cleft, thereby enhancing neurotransmission in key brain pathways associated with attention, motivation, and wakefulness.
Medical uses of dextroamphetamine
Dextroamphetamine has two primary FDA-approved therapeutic uses:
- Attention-Deficit/Hyperactivity Disorder (ADHD): For individuals with ADHD, dextroamphetamine helps to manage core symptoms such as inattention, hyperactivity, and impulsivity. It increases attention span and decreases restlessness, making it part of a comprehensive treatment plan that often includes psychological and educational interventions.
- Narcolepsy: As a potent CNS stimulant, dextroamphetamine is used to treat narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and sudden attacks of sleep. It helps to promote wakefulness and alertness during the day.
Forms and administration
Dextroamphetamine is available in several forms to suit different therapeutic needs, and the choice depends on the patient's condition and treatment goals:
- Immediate-Release (IR) Tablets: These are taken multiple times a day to provide short-term symptom control. The effects typically last 4 to 6 hours.
- Extended-Release (XR) Capsules: These capsules are taken once daily in the morning and are designed to provide a more sustained release of the medication over 8 to 12 hours, reducing the need for multiple daily doses.
- Oral Solution: A liquid form is also available for those who have difficulty swallowing tablets or capsules.
Side effects and precautions
Like all medications, dextroamphetamine has potential side effects, ranging from common and mild to severe. It is crucial to be aware of these and to discuss any concerns with a healthcare provider. Common side effects include:
- Increased heart rate and blood pressure
- Insomnia or trouble sleeping
- Decreased appetite and weight loss
- Dry mouth
- Headaches
- Nervousness or restlessness
More serious side effects are possible and require immediate medical attention:
- Serious cardiovascular problems, including chest pain, heart attack, or stroke.
- Mental health issues, such as new or worsened psychotic or manic symptoms.
- Changes in circulation, including Raynaud's phenomenon, which affects blood flow to the fingers and toes.
- Seizures.
Patients should inform their doctor of any pre-existing conditions, especially heart problems, high blood pressure, history of substance abuse, or certain mental health disorders, as these can increase the risk of serious side effects. Dextroamphetamine is classified as a Schedule II controlled substance due to its high potential for misuse and dependence.
Dextroamphetamine vs. Adderall
While dextroamphetamine and Adderall are both CNS stimulants used for ADHD and narcolepsy, they have different compositions. The choice between them depends on the individual's needs and how their body responds to each medication.
| Feature | Dextroamphetamine (e.g., Dexedrine) | Adderall (Mixed Amphetamine Salts) |
|---|---|---|
| Composition | Contains only the d-amphetamine isomer, known for stronger CNS effects. | A combination of four amphetamine salts: dextroamphetamine saccharate, dextroamphetamine sulfate, amphetamine aspartate, and amphetamine sulfate. The ratio is 3:1 dextroamphetamine to levoamphetamine. |
| Potency | Generally considered stronger on a milligram-for-milligram basis due to its purer d-amphetamine concentration. | Offers a more balanced effect, with the l-amphetamine component contributing to a slightly slower onset and longer-lasting effect for some individuals. |
| Effects | More potent and focused on mental concentration and alertness. | Combines mental focus with a boost in physical energy due to the mix of isomers. |
| Onset/Duration | Available in both immediate-release (4-6 hours) and extended-release (8-12 hours) versions. | Available in immediate-release (4-6 hours) and extended-release (up to 12 hours) versions. |
Conclusion
Dextroamphetamine is a powerful and effective CNS stimulant for the treatment of ADHD and narcolepsy. It increases key neurotransmitters in the brain, leading to improved focus, attention, and wakefulness. While it offers significant benefits, it is a controlled substance with a high potential for misuse and dependence, and its use requires careful medical supervision due to the risk of side effects, particularly cardiovascular and psychiatric ones. Patients should work closely with their healthcare provider to determine the right treatment plan and dosage, considering potential risks and benefits. For more comprehensive drug information, refer to the U.S. National Library of Medicine's MedlinePlus database.
