Dextroamphetamine

Uses

Dextroamphetamine is a sympathomimetic agent used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy.

Dextroamphetamine is indicated for the treatment of attention deficit hyperactivity disorder (ADHD).

Dextroamphetamine is also used to associated treatment for these conditions: Attention Deficit Hyperactivity Disorder (ADHD), Narcolepsy

How Dextroamphetamine works

The exact mechanism of amphetamines as a class is not known. Dextroamphetamine acts by preventing reuptake, increasing release, and stimulating reverse-transport of dopamine in synaptic clefts in the striatum. Newer evidence shows amphetamines may also alter the number of dopamine transporters in synaptic clefts.

Toxicity

Dextroamphetamine has been shown to be teratogenic and embryotoxic in mice at 41 times the maximum human dose. These effects were not seen in rat or rabbit studies, and the effects on human pregnancy have not been studied. The risk and benefit of use during pregnancy should be weighed as bone deformities, tracheoesophageal fistula, anal atresia, low birthweight, and withdrawl have been reported in the children of mothers who were taking dextroamphetamine during pregnancy. Mothers should not take amphetamines while nursing as the drug is excreted in breast milk. Long term effects of dextroamphetamine have not bee determined in pediatric patients and dextroamphetamine should be avoided in children under 3 years.

Food Interaction

• Avoid fruit juice. Fruit juice may acidify the gastrointestinal tract, decreasing absorption of amphetamines.

[Moderate] GENERALLY AVOID: Alcohol may potentiate the cardiovascular effects of amphetamines.

The exact mechanism of interaction is unknown.

In one study, concurrent administration of methamphetamine (30 mg intravenously) and ethanol (1 gm

This increases cardiac work and myocardial oxygen consumption, which may lead to more adverse cardiovascular effects than either agent alone.

Subjective effects of ethanol were diminished in the eight study subjects, but those of methamphetamine were not affected.

The pharmacokinetics of methamphetamine were also unaffected except for a decrease in the apparent volume of distribution at steady state.

The interaction was suspected in a case report of a 20-year-old male who experienced retrosternal chest pain shortly after drinking alcohol and taking a double dose of his amphetamine

The patient had no family history of cardiovascular diseases, and his past medical history was remarkable only for ADHD.

Prior to the episode, the patient had not taken his medication for weeks and had been drinking whiskey the previous three nights before going to bed.

The patient was diagnosed with myocardial infarction likely secondary to amphetamine-induced coronary vasospasm.

MANAGEMENT: Concomitant use of amphetamines and alcohol should be avoided if possible, especially in patients with a history of heart disease.

Dextroamphetamine Hypertension interaction

[Major] The use of CNS stimulants is contraindicated in patients with significant cardiovascular impairment such as uncompensated heart failure, severe coronary disease, severe hypertension (including that associated with hyperthyroidism or pheochromocytoma), cardiac structural abnormalities, serious arrhythmias, etc.

Sudden death has been reported in adults and children taking CNS stimulant treatment.

Additionally, stroke, myocardial infarction, chest pain, syncope, arrhythmias and other symptoms have been reported in adults under treatment.

A careful assessment of the cardiovascular status should be done in patients being considered for treatment.

This includes family history, physical exam and further cardiac evaluation (EKG and echocardiogram).

Patients who develop symptoms should have a detailed cardiac evaluation and if needed, treatment should be suspended.

[Major] CNS stimulant medications have shown to increase blood pressure, and their use might be contraindicated in patients with severe hypertension.

Caution should be used when administering to patients with preexisting high blood pressure and other cardiovascular conditions.

All patients under treatment should be regularly monitored for changes in blood pressure and heart rate.

Dextroamphetamine Drug Interaction

Major: duloxetine, duloxetine, escitalopram, escitalopram, fluoxetine, fluoxetineUnknown: amphetamine / dextroamphetamine, amphetamine / dextroamphetamine, amphetamine / dextroamphetamine, amphetamine / dextroamphetamine, pregabalin, pregabalin, cyanocobalamin, cyanocobalamin, cholecalciferol, cholecalciferol, lisdexamfetamine, lisdexamfetamine, alprazolam, alprazolam

Dextroamphetamine Disease Interaction

Major: cardiovascular, glaucoma, agitation, cardiac disease, glaucoma, hypertension, liver disease, psychiatric disorders, substance abuse, ticsModerate: bipolar disorders, psychotic disorders, renal dysfunction, seizure disorders, diabetics

Volume of Distribution

195L.

Elimination Route

Bioavailability data of dextroamphetamine is not readily available, however there is no difference in bioavailability when taken with or without a meal.

Half Life

11.75 hours. In a study of post-stroke patients the half life was 16.0 hours in females and 12.4 hours in males. Studies in healthy populations show a half life of 7.9 hours.

Clearance

17L/h.

Elimination Route

A third of the drug is eliminated renally.

Innovators Monograph

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