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CNS stimulant (amphetamine)

Dextroamphetamine

Dextroamphetamine is a central nervous system stimulant of the amphetamine class used primarily to treat attention-deficit/hyperactivity disorder (ADHD) and narcolepsy. It is the dextrorotatory stereoisomer of amphetamine and is a Schedule II controlled substance in the United States. The most testable fact is that it increases synaptic dopamine and norepinephrine by promoting their release and blocking reuptake, while also inhibiting monoamine oxidase.

Practice questionsHigh-yield facts
Drug classCNS stimulant (amphetamine)
MechanismIncreases dopamine and norepinephrine release, blocks reuptake
Main usesADHD, narcolepsy
Key adverse effectCardiovascular effects, abuse potential, growth suppression in children
7 min readFor medical studentsUpdated 2026-10-14

Mechanism of action

Dextroamphetamine acts through multiple mechanisms to increase catecholamine neurotransmission in the central nervous system. Its primary actions include:

  • Promotes release of dopamine and norepinephrine from presynaptic terminals by reversing the action of monoamine transporters (DAT and NET), causing these transporters to work in reverse and pump neurotransmitters out into the synapse
  • Blocks reuptake of dopamine and norepinephrine by competitively inhibiting DAT and NET
  • Inhibits monoamine oxidase (MAO), reducing the enzymatic breakdown of catecholamines
  • Increases release and blocks reuptake of serotonin to a lesser extent

The result is increased synaptic concentrations of dopamine and norepinephrine, particularly in the prefrontal cortex, striatum, and other dopaminergic pathways. In ADHD, this enhances executive function, attention, and impulse control. The drug's wake-promoting effects in narcolepsy relate to increased catecholaminergic tone in arousal pathways.

Dextroamphetamine is approximately twice as potent as the levorotatory isomer at increasing dopamine release, making it more pharmacologically active than racemic amphetamine on a per-milligram basis.

High-yield for exams
  • Dextroamphetamine increases synaptic dopamine and norepinephrine by promoting release, blocking reuptake, and inhibiting MAO
  • Schedule II controlled substance with high abuse potential (black box warning for dependence)
  • Contraindicated with MAOIs—can cause hypertensive crisis; requires 14-day washout period
  • Urinary pH critically affects half-life: acidic urine increases excretion, alkaline urine prolongs action
  • Major cardiovascular risks include sudden cardiac death (in those with structural abnormalities), hypertension, tachycardia, and arrhythmias
  • Chronic pediatric use causes growth suppression; monitor height and weight every 3-6 months
  • Can precipitate psychosis, mania, or hallucinations, especially in patients with underlying psychiatric disorders
  • Serotonin syndrome risk when combined with SSRIs, SNRIs, MAOIs, or other serotonergic agents

Indications

Dextroamphetamine is FDA-approved for:

Attention-Deficit/Hyperactivity Disorder (ADHD)

Approved for children (typically 3 years and older), adolescents, and adults as part of a comprehensive treatment program that includes psychological, educational, and social measures. It improves attention span, decreases impulsivity, and reduces hyperactivity.

Narcolepsy

Used to reduce excessive daytime sleepiness and cataplexy episodes in patients with narcolepsy. It promotes wakefulness and alertness.

Off-Label Uses

Off-label uses include treatment-resistant depression (as adjunctive therapy) and rarely for obesity, though the latter is not recommended due to abuse potential and limited long-term efficacy. Dosing follows product labeling and should be individualized based on patient response and tolerability.

Pharmacokinetics

  • Absorption: Rapidly absorbed from the gastrointestinal tract. Extended-release formulations provide sustained plasma levels over 8-12 hours
  • Distribution: Widely distributed throughout the body, including the CNS. Concentrates in brain tissue at levels higher than plasma
  • Metabolism: Primarily hepatic via CYP2D6-mediated hydroxylation and subsequent conjugation. Active metabolites are minimal
  • Excretion: Excreted in urine. Approximately 30-40% is excreted unchanged. Urinary pH significantly affects excretion rate—acidic urine (pH <6.5) increases excretion, while alkaline urine (pH >7.5) prolongs half-life
  • Half-life: Approximately 10-12 hours in adults (range 9-14 hours), with significant inter-individual variation depending on urinary pH and hepatic function
  • Onset: Immediate-release formulations begin working within 30-60 minutes; extended-release formulations within 1-2 hours

Adverse effects

Dextroamphetamine carries a black box warning for high abuse potential, which may lead to drug dependence. It is a Schedule II controlled substance.

Common Adverse Effects

  • Cardiovascular: Tachycardia, palpitations, hypertension, increased blood pressure and heart rate
  • CNS: Insomnia, restlessness, nervousness, anxiety, irritability, dizziness, headache, tremor
  • Gastrointestinal: Decreased appetite, weight loss, dry mouth, nausea, abdominal pain, constipation
  • Psychiatric: Mood changes, agitation, exacerbation of underlying psychiatric disorders

Serious Adverse Effects

  • Cardiovascular toxicity: Sudden cardiac death (rare), myocardial infarction, stroke, serious arrhythmias, especially in patients with structural cardiac abnormalities
  • Psychiatric symptoms: New-onset or worsening psychosis, mania, aggression, hallucinations (visual and tactile), particularly at higher doses
  • Growth suppression: Slowing of growth rate and weight gain in pediatric patients with chronic use; monitoring of height and weight is recommended
  • Peripheral vasculopathy: Including Raynaud phenomenon and digital ulceration in rare cases
  • Serotonin syndrome: When combined with serotonergic agents
  • Seizures: Lowering of seizure threshold
  • Priapism: Rare but serious adverse effect requiring immediate medical attention

Long-Term Concerns

Chronic use can lead to tolerance, psychological dependence, and withdrawal symptoms (fatigue, depression, hypersomnia) upon discontinuation. Abrupt cessation after prolonged high-dose use may precipitate severe depression and suicidal ideation.

Contraindications and warnings

Absolute Contraindications

  • Hypersensitivity to amphetamines or any component of the formulation
  • Concurrent or recent (within 14 days) MAOI use: Risk of hypertensive crisis
  • Symptomatic cardiovascular disease: Including moderate to severe hypertension, advanced arteriosclerosis, structural cardiac abnormalities, cardiomyopathy, serious arrhythmias, coronary artery disease
  • Hyperthyroidism: Amplifies cardiovascular effects
  • Glaucoma: Particularly angle-closure glaucoma, as amphetamines cause mydriasis
  • Agitated states or history of drug abuse

Warnings and Precautions

  • Cardiovascular assessment: Screen for cardiac disease before initiating therapy. Sudden death has been reported in children and adolescents with structural cardiac abnormalities. Consider ECG in patients with cardiovascular risk factors
  • Psychiatric evaluation: Screen for bipolar disorder, psychosis, and other psychiatric conditions. Stimulants may precipitate mixed/manic episodes in bipolar disorder or exacerbate psychotic symptoms
  • Growth monitoring: Monitor height and weight in pediatric patients. Consider drug holidays if growth suppression occurs
  • Seizure risk: Use with caution in patients with a history of seizures; may lower seizure threshold
  • Pregnancy: Category C. Amphetamines cross the placenta and have been associated with premature birth, low birth weight, and neonatal withdrawal symptoms. Use only if benefit outweighs risk
  • Breastfeeding: Excreted in breast milk. Potential for serious adverse reactions in nursing infants; weigh risks and benefits
  • Visual disturbances: May cause difficulty with accommodation and blurred vision
  • Blood pressure and heart rate: Monitor regularly during treatment

Drug interactions

Major Interactions

  • MAOIs (phenelzine, tranylcypromine, selegiline): Contraindicated combination. Can cause hypertensive crisis, hyperthermia, seizures, and death. Allow at least 14 days between MAOI discontinuation and amphetamine initiation
  • Serotonergic drugs (SSRIs, SNRIs, TCAs, triptans, St. John's wort): Increased risk of serotonin syndrome, especially at higher doses
  • Acidifying agents (ammonium chloride, sodium acid phosphate, vitamin C): Increase urinary excretion and decrease amphetamine levels and efficacy
  • Alkalinizing agents (sodium bicarbonate, acetazolamide, antacids): Decrease urinary excretion, prolonging half-life and increasing toxicity risk

Moderate Interactions

  • Antihypertensives: Amphetamines may antagonize hypotensive effects; monitor blood pressure
  • Anticonvulsants (phenytoin, phenobarbital): Amphetamines may decrease seizure threshold; dose adjustments may be needed
  • Proton pump inhibitors and H2 blockers: By increasing gastric pH, may enhance amphetamine absorption and effect
  • TCAs (desipramine, imipramine): Amphetamines enhance TCA effects; increased risk of cardiovascular effects
  • CYP2D6 inhibitors (quinidine, fluoxetine, paroxetine): May increase amphetamine levels
  • Gastrointestinal acidifying agents: May reduce absorption of extended-release formulations
  • Haloperidol and chlorpromazine: Antipsychotics inhibit central stimulant effects of amphetamines
  • Lithium: May inhibit anorectic and stimulant effects of amphetamines
  • Adrenergic blockers: Amphetamines antagonize hypotensive effects of adrenergic blockers

Clinical pearls

  • Drug holidays: Consider scheduled breaks (weekends, summer vacations) in pediatric patients to assess continued need and minimize growth suppression
  • Urinary pH matters: Acidic urine (high-protein diet, cranberry juice, vitamin C) increases excretion and shortens duration of action. Alkaline urine (antacids, high-vegetable diet, sodium bicarbonate) prolongs effects. This is clinically relevant for both efficacy and toxicity
  • Afternoon dosing caution: Avoid late-day dosing of immediate-release formulations to minimize insomnia. Extended-release formulations are typically given once daily in the morning
  • Tolerance: Therapeutic tolerance is uncommon at recommended doses. If efficacy wanes, consider compliance issues, dose timing, or alternative diagnoses before dose escalation
  • Cardiovascular screening: Although controversial, sudden cardiac death in children prompted recommendations for cardiovascular assessment. ECG is not routinely required but should be considered if cardiac history or symptoms exist
  • Weight and growth: Monitor every 3-6 months in children. If clinically significant suppression occurs, consider dose reduction, drug holidays, or alternative therapies
  • Rebound phenomena: Some patients experience symptom rebound as medication wears off. Extended-release formulations or afternoon immediate-release supplementation may help
  • Pregnancy and lactation: Amphetamines are lipophilic and cross both the placenta and into breast milk. Neonatal withdrawal and lactation exposure are real concerns
  • Toxicity presentation: Acute toxicity presents with agitation, hyperthermia, tachycardia, hypertension, mydriasis, tremor, and potentially seizures or cardiac arrhythmias. Severe cases may cause rhabdomyolysis and acute kidney injury
  • Screening for diversion: As a Schedule II substance with high street value, assess for signs of misuse, diversion, or "doctor shopping." Consider prescription monitoring programs
  • Not first-line for depression: While sometimes used as augmentation in treatment-resistant depression, amphetamines are not first-line antidepressants due to abuse potential and limited long-term data
  • Differentiate from methylphenidate: Both are first-line for ADHD, but amphetamines have slightly higher dopamine-to-norepinephrine selectivity and may be more potent on a per-milligram basis. Methylphenidate primarily blocks reuptake rather than promoting release
Mnemonic

AMPHETAMINE adverse effects: Agitation, Myocardial infarction, Psychosis, Hypertension, Excitement, Tachycardia, Anorexia, Mania, Insomnia, Nausea, Euphoria (abuse potential)

Practice questions

1. A 9-year-old boy with ADHD has been taking dextroamphetamine for 18 months. At a routine follow-up visit, his mother reports that his symptoms are well controlled, but she is concerned that he seems shorter than his classmates. Growth charts show his height has fallen from the 60th percentile to the 25th percentile, while his weight has dropped from the 55th to the 20th percentile. What is the most appropriate next step in management?

Answer: C. Growth suppression is a known adverse effect of chronic stimulant use in children. The most appropriate initial management is to implement drug holidays (medication-free periods on weekends and during school vacations) to minimize exposure while maintaining therapeutic benefit during school. Growth should be monitored closely. Immediate discontinuation is not necessary if the medication is otherwise effective. While growth often normalizes after stopping stimulants or after puberty, proactive intervention is warranted. Endocrine evaluation is not indicated unless growth suppression is severe or other hormonal abnormalities are suspected.

2. A 28-year-old woman with narcolepsy presents to the emergency department with severe headache, diaphoresis, palpitations, and blood pressure of 210/115 mmHg. She started taking dextroamphetamine 2 weeks ago. Her medication list also includes an antidepressant she started 3 weeks ago for depression. Which antidepressant is most likely responsible for this interaction?

Answer: C. This patient is presenting with a hypertensive crisis due to the combination of dextroamphetamine with phenelzine, a monoamine oxidase inhibitor (MAOI). This combination is contraindicated because MAOIs prevent the breakdown of catecholamines, and when combined with amphetamines (which increase catecholamine release), the result is excessive accumulation of norepinephrine and dopamine, leading to severe hypertension, hyperthermia, and potentially fatal complications. At least 14 days must elapse after discontinuing an MAOI before starting an amphetamine. While SSRIs (fluoxetine, sertraline) can increase serotonin syndrome risk with amphetamines, they do not typically cause hypertensive crisis.

3. A 35-year-old man with ADHD reports that his dextroamphetamine, which had been working well for months, suddenly seems less effective. He now experiences symptom breakthrough by early afternoon despite taking the medication as prescribed each morning. He has been drinking cranberry juice daily for a urinary tract infection. Which factor most likely explains the reduced drug efficacy?

Answer: C. Cranberry juice acidifies the urine, which significantly increases the renal excretion of dextroamphetamine and shortens its half-life, leading to reduced efficacy and shorter duration of action. Urinary pH is a critical determinant of amphetamine pharmacokinetics—acidic urine (pH <6.5) enhances excretion, while alkaline urine (pH >7.5) prolongs it. This acute change in efficacy coinciding with new cranberry juice consumption points to the pH-dependent excretion mechanism. Therapeutic tolerance to amphetamines at prescribed doses is uncommon, and cranberry juice does not affect gastrointestinal absorption or hepatic metabolism of the drug.

Frequently asked questions

How does dextroamphetamine work?

Dextroamphetamine increases concentrations of dopamine and norepinephrine in the synapse through three mechanisms: promoting their release from presynaptic terminals by reversing monoamine transporters, blocking their reuptake, and inhibiting monoamine oxidase which breaks them down. These actions enhance catecholaminergic neurotransmission in brain regions controlling attention, executive function, and arousal. In ADHD, this improves focus and impulse control; in narcolepsy, it promotes wakefulness.

What are the side effects of dextroamphetamine?

Common side effects include decreased appetite and weight loss, insomnia, nervousness, increased heart rate and blood pressure, headache, dry mouth, and abdominal discomfort. Serious adverse effects include cardiovascular events such as sudden cardiac death (rare, especially with structural heart abnormalities), stroke, or myocardial infarction; psychiatric symptoms including new or worsening psychosis, mania, and hallucinations; growth suppression in children; and seizures. It also carries high abuse potential and risk of psychological dependence.

Is dextroamphetamine a controlled substance?

Yes, dextroamphetamine is a Schedule II controlled substance in the United States, the most restrictive category for medications with accepted medical use. This classification reflects its high potential for abuse and risk of severe psychological or physical dependence. Prescriptions cannot be refilled and require a new written or electronic prescription for each fill. The drug carries a black box warning emphasizing this abuse potential and the need for careful patient selection and monitoring.

Can you take dextroamphetamine during pregnancy?

Dextroamphetamine is Pregnancy Category C, meaning risk cannot be ruled out. It crosses the placenta and has been associated with adverse outcomes including premature birth, low birth weight, and neonatal withdrawal symptoms in infants exposed during gestation. Use during pregnancy should only occur if the potential benefit justifies the potential risk to the fetus. Women of childbearing potential should discuss pregnancy planning with their physician, and the medication should be discontinued if pregnancy occurs unless continuation is deemed medically necessary.

Dextroamphetamine vs methylphenidate—what is the difference?

Both are first-line stimulants for ADHD, but they differ in mechanism and potency. Dextroamphetamine promotes release of dopamine and norepinephrine while also blocking reuptake and inhibiting MAO. Methylphenidate primarily blocks reuptake without promoting release. Dextroamphetamine tends to have slightly higher dopamine selectivity and is generally more potent milligram-for-milligram. Both are Schedule II controlled substances with similar adverse effect profiles, though individual patient response varies and selection is often based on tolerability and duration of action needed.

Conditions it is used for

Attention-deficit/hyperactivity disorderADHDNarcolepsyExcessive daytime sleepinessTreatment-resistant depressionCataplexy
amphetaminelisdexamfetaminemethylphenidateatomoxetinemodafinilbupropionguanfacineclonidine

Sources and further reading

DailyMed (FDA labels)StatPearls (NCBI Bookshelf)MedlinePlusWHO ATC/DDD index: N06BA02

Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.