Technical Information about Amphetamines

This information is for clinicians' use.

Warning
Amphetamines have a potential for abuse. They should be tried in weight reduction programs only for patients in whom other therapies have been ineffective and only under a doctor's supervision.  Administration of amphetamines for prolonged periods of time in obesity may lead to drug dependence and should be avoided.  When tolerance to the "anorectic" effect develops, do not increase the recommended in an attempt to increase the effect.  Slowly discontinue the drug over a period of days or weeks.

Avoid use in patients with advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, glaucoma, agitated states, a history of drug abuse, and known hypersensitivity or idiosyncrasy to the sympathomimetic amines.

Do not take within 14 days following the administration of monoamine oxidase inhibitors (hypertensive crises may result).

Administration of amphetamine may exacerbate symptoms of some behavior disturbances and thought disorder.  Data are inadequate to determined whether chronic administration of amphetamine may be associated with growth inhibition; therefore, growth should be monitored during treatment.

Amphetamines may enhance the activity of tricyclic or sympathomimetic agents.  Using d-amphetamine with desipramine or protriptyline and possibly other tricyclics causes striking and sustained increases in the concentration of d-amphetamine in the brain; cardiovascular effects can also be potentiated.

Amphetamines have been reported to exacerbate (and ameliorate) motor and phonic tics and Tourette's syndrome.  Therefore, clinical evaluation for tics and Tourette's syndrome in children and their families should be carried out before stimulant medications are given.

The amphetamines are Schedule II controlled substances and orders for them will not be filled at pharmacies without a written prescription.  Attention should be paid to the possibility of patients, particularly teen-agers or young adults, obtaining amphetamines for non-therapeutic use or for distribution to others. 

Amphetamines have been extensively abused. Tolerance, extreme psychological dependence, and severe social disability have occurred. There are reports of patients who have increased the dosage to many times that recommended.  Abrupt cessation following prolonged high dosage administration results in extreme fatigue and mental depression.

Manifestations of chronic intoxication with amphetamines include delusions of skin parasites, marked insomnia, irritability, hyperactivity, and personality changes. The most severe manifestation of chronic intoxication is psychosis, often clinically indistinguishable from schizophrenia. This is rare with oral amphetamines.   Paranoia occurs more often early on the course of treatment and most often subsides within days or weeks of discontinuation.

Deaths, most likely from cardiovascular causes has been reported in patients taking amphetamines.   Caution should be taken in any patients with preexisting heart disease or a family history of fatal heart disease at an early age.

Use caution in prescribing amphetamines for patients with hypertension.  If hypertension occurs with amphetamine use, but the amphetamines are being helpful to the patient, anti-hypertensive medication can be used concurrently.

Amphetamine has been shown to have embryotoxic and teratogenic effects when administered to mice in doses approximately 41 times the maximum human dose. There are no adequate and well-controlled studies in pregnant women.  Amphetamines should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Infants born to mothers dependent on amphetamines have a higher risk of premature delivery and low birth weight. Also, these infants may experience symptoms of withdrawal as demonstrated by dysphoria, including agitation and significant lassitude for a few days.

Amphetamines are excreted in human milk.  Mothers taking amphetamines should be advised to refrain from nursing.