Amphetamine is indicated for the treatment of attention-deficit/hyperactivity disorders (ADHD) as well as for the treatment of central nervous system disorders such as narcolepsy.
Dextroamphetamine is a sympathomimetic agent used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy
ADHD is a complex disorder associated with the substantial heterogeneity in etiology, clinical presentation, and treatment outcome. ADHD comes from a complex interplay between interdependent genetic and non-genetic factors which cause complex mental disorders in children and teenagers.
On the other hand, narcolepsy is a chronic sleep disorder typically resenting during adolescence and characterized by excessive daytime sleepiness.
Amphetamine is also being used nowadays off-label for the treatment of obesity, depression and chronic pain.
(Dextro)Amphetamine may also be used for purposes not listed in this medication guide.
From its mechanism of action, it has been demonstrated that amphetamine augments the concentration of noradrenaline in the prefrontal cortex and dopamine in the striatum on a dose and time-dependent manner. The indistinct release of neurotransmitters which include adrenaline is known to produce cardiovascular side effects.
There are old reports of a cognitive enhancement related to the administration of amphetamine in which improvements in intelligence test scores were reported. In ADHD, amphetamine has been largely showed to produce remarkable improvements in school performance, behavior, and demeanor.
Dextroamphetamine is a noncatecholamine, sympathomimetic amine that acts as a CNS stimulant. Dextroamphetamine raises systolic and diastolic blood pressure, acts as a weak bronchodilator, and also acts as a respiratory stimulant. The general mechanism of action of dextroamphetamine has not been well established.
It is important to consider that amphetamine has a very similar structure to the catecholamine neurotransmitters mainly on the presence of a long planar conformation, the presence of an aromatic ring and nitrogen in the aryl side chain. Amphetamine, as well as other catecholamines, is taken into presynaptic nerve terminals by the association with two sodium ions and one chloride ion. The complex of the amphetamine with the ions is actively transported by monoamine reuptake transporters. As amphetamine acts competitively with the endogenous monoamines, the greater the number of amphetamines the more internalized amphetamine will be found.
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.
Metabolism: Amphetamine is known to be metabolized by the liver under the action of the CYP2D6. The metabolic pathway of amphetamine is mainly defined by aromatic hydroxylation, aliphatic hydroxylation, and n-dealkylation. Dextroamphetamine is metabolized by cytochrome P-450 2D6 in the liver to 4-hydroxyamphetamine and later conjugated by sulfotransferase or glucoronyltransferase.
Absorption: Amphetamine is well absorbed in the gut and complete amphetamine absorption is usually done after 4-6 hours. Bioavailability data of dextroamphetamine is not readily available, however there is no difference in bioavailability when taken with or without a meal.
Route of elimination: The elimination of amphetamine is mainly via the urine from which about 40% of the excreted dose is found as unchanged amphetamine. About 90% of the administered amphetamine is eliminated 3 days after oral administration. A third of the dextroamphetamine is eliminated renally.
Half life: The half-life of amphetamine highly depends on the isomer. For d-amphetamine, the reported half-life is of approximately 9-11 hours while for l-amphetamine the half-life is reported to be of 11-14 hours. For dextroamphetamine 11.75 hours.
All medicines may cause side effects, but many people have no, or minor, side effects. Some medical conditions may interact with (Dextro)Amphetamine.
Tell your doctor or pharmacist if you have any medical conditions.
Some of the neurologic effects have been shown to be agitation, aggressive behavior, irritability, headache, and hallucinations. In the cardiovascular site, there have been reports of arrhythmia, cardiomyopathy, myocardial infarction or ischemic stroke. Lastly, in the GI tract, there are reports if abdominal pain, vomiting, diarrhea, cramps, anorexia and GI hemorrhage.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.
