What is Dexfenfluramine?

Dexfenfluramine is a anorectic drug used to aid in weight loss. It is an appetite suppressant that functions by causing the release of the neurochemical serotonin. This is done by disrupting serotonin storage sites in the brain. The released serotonin causes a loss of appetite, and, in many people, also causes a feeling of fullness.

This is one of several similar weight-loss supplements that was produced and marketed in the late 1980s and early 1990s. All of these supplements are anorectic, which is derived from Greek and translates as without appetite. Dexfenfluramine was also used to create a similar compound, fenfluramine, which is a combination of dexfenfluramine and levofenfluramine.

These two constituent parts of fenfluramine are stereoisomers. This means that they have the same chemical components and molecular formula, but are structured differently in three-dimensional space. These two compounds are also in a particular class of stereoisomers known as enantiomers. Compounds which are enantiomers are mirror-images of one another, analogous to a right and left hand. They cannot be superimposed on one another, and are often described as being the same, but opposite.

Dexfenfluramine was removed from the market by the United States Food and Drug Administration (FDA) in 1997, after reports surfaced indicating that it caused serious cardiovascular side effects. These included heart valve disease and cardiac fibrosis. Dexfenfluramine was marketed in the United States under the name Redux®, by Wyeth-Ayerst Laboratories.

Fenfluramine was removed from stores at the same time as dexfenfluramine. Prior to its removal, it saw the most use as the drug Adifax&trade. This medication was also combined with another, phentermine, and together the combinations known as phen-fen. By 2004, phen-fen had almost disappeared from the market, but spawned a mass tort, or class action lawsuit, which included over 50,000 alleged victims, all of whom had experienced adverse side effects from the drug. The total liability of the tort was estimated at $14 billion US Dollars (USD).

Doses of dexfenfluramine are taken orally, typically in capsule form. The daily recommended intake is two 15 milligram (mg) capsules, always taken with food. The capsules are usually white in color, and opaque, and have the name Redux® stamped on them, along with three vertical black bands.

Other drugs that have potential negative interactions with dexfenfluramine include blood pressure medications, and those used to treat diabetes. Also, monoamine oxidase (MAO) inhibitors, which are used to combat depression, can have unwanted side effects if taken with this weight loss drug. In some cases, symptoms, such as anxiety and abdominal pain, can result if use of this weight loss drug is suspended.