Benzphetamine

Benzphetamine (brand name: Didrex) is an anti-obesity drug marketed under this brand in the USA by Pharmacia. Benzphetamine is used as a short term adjunct in management of exogenous obesity. It is closely related to amphetamine.

Additional recommended knowledge

Essential Laboratory Skills Guide

What is the Sensitivity of my Balance?

Safe Weighing Range Ensures Accurate Results

Pharmacology

Benzphetamine is a sympathomimetic amine that is anorexic in action. The main function of this drug is to reduce hunger, which in turn reduces caloric intake.

Although the mechanism of action of the sympathomimetic appetite suppressants in the treatment of obesity is not fully known, these medications have pharmacological effects similar to those of amphetamines. Amphetamine and related sympathomimetic medications (such as benzphetamine) are thought to stimulate the release of norepinephrine and/or dopamine from storage sites in nerve terminals in the lateral hypothalamic feeding center, thereby producing a decrease in appetite. This release is mediated by the binding of benzphetamine to centrally located adrenergic receptors. Tachyphylaxis and tolerance have been demonstrated with all drugs of this class in which these phenomena have been looked for.

Contraindications

Benzphetamine is contraindicated in patients with advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyper-thyroidism, known hypersensitivity or idiosyncrasy to sympathomimetic amines, and glaucoma. Benzphetamine should not be given to patients who are in an agitated state or who have a history of drug abuse.

Controlled substance classification

Benzphetamine is unique in its classification as a Schedule III drug in the United States. (Most members of the amphetamine family are classified in the more highly-regulated Schedule II.) It's notable that benzphetamine is metabolized by the human body into amphetamine and methamphetamine metabolites, making it one of the very few drugs to undergo in vivo conversion to a substance of higher addiction and abuse potential. Benzphetamine itself does not have a such a high abuse potential (Schedule III) because any administration route (ingested, insufflated, injected, etc.) would still have a sustained release due to the amount of time it would take the liver to metabolize it into amphetamine and methamphetamine. A person using benzphetamine recreationally may accidentally overdose because the peak high would appear much later, if there is a high at all.