Home / Drugs / Starting with D /
indicationUsed to treat attention deficit hyperactivity disorder (ADHD).
pharmacologyAmphetamines such as dextroamphetamine are noncatecholamine, sympathomimetic amines with CNS stimulant activity. Peripheral actions include elevations of systolic and diastolic blood pressures and weak bronchodilator and respiratory stimulant action. There is neither specific evidence that clearly establishes the mechanism whereby amphetamines produce mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the central nervous system.
mechanism of actionThe exact mechanism of action is not known. Dextroamphetamine stimulates the release of norepinephrine from central adrenergic receptors. At higher dosages, it causes release of dopamine from the mesocorticolimbic system and the nigrostriatal dopamine systems by reversal of the monoamine transporters. Dextroamphetamine may also act as a direct agonist on central 5-HT receptors and may inhibit monoamine oxidase (MAO). In the periphery, amphetamines are believed to cause the release of noradrenaline by acting on the adrenergic nerve terminals and alpha- and beta-receptors. Modulation of serotonergic pathways may contribute to the calming affect.
toxicityIn rats, the oral LD50 of dextroamphetamine sulfate is 96.8 mg/kg. Manifestations of acute overdosage with amphetamines include restlessness, tremor, hyperreflexia, rhabdomyolysis, rapid respiration, hyperpyrexia, confusion, assaultiveness, hallucinations, panic states. Fatigue and depression usually follow the central stimulation. Cardiovascular effects include arrhythmias, hypertension or hypotension, and circulatory collapse. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Fatal poisoning is usually preceded by convulsions and coma.
absorptionOral bioavailability is over 75%.
half life10-28 hours (average is approximately 12 hours)
drug interactionsChlorpromazine: Decreased anorexic effect, may increases psychotic symptoms
Fluoxetine: Risk of serotoninergic syndrome
Fluphenazine: Decreased anorexic effect, may increase psychotic symptoms
Fluvoxamine: Risk of serotoninergic syndrome
Guanethidine: Dextroamphetamine may decrease the effect of guanethidine.
Isocarboxazid: Possible hypertensive crisis
Mesoridazine: Decreased anorexic effect, may increase psychotic symptoms
Methotrimeprazine: Decreased anorexic effect, may increase psychotic symptoms
Paroxetine: Risk of serotoninergic syndrome
Perphenazine: Decreased anorexic effect, may increase psychotic symptoms
Phenelzine: Possible hypertensive crisis
Prochlorperazine: Decreased anorexic effect, may increase pyschotic symptoms
Promethazine: Decreased anorexic effect, may increase pyschotic symptoms
Propericiazine: Decreased anorexic effect, may increase pyschotic symptoms
Rasagiline: Possible hypertensive crisis
Thioridazine: Decreased anorexic effect, may increase psychotic symptoms
Tramadol: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.
Trandolapril: Dextroamphetamine may reduce the efficacy of Trandolapril.
Tranylcypromine: The MAO inhibitor, Tranylcypromine, may increase the vasopressor effect of the amphetamine, Dextroamphetamine. Concomitant therapy should be avoided.
Trifluoperazine: Decreased anorexic effect, may increase psychotic symptoms
Triprolidine: Triprolidine may reduce the sedative effect of the antihistamine, Dextroamphetamine.