Fen-Phen Overview

“Fen-Phen” Defined

Fen-Phen is the combination of the drugs called fenfluramine and phentermine. Phentermine is also combined with dexfenfluramine and termed as “dexfen-phen.” Fenfluramine or “fen” and phentermine or “phen” belong to prescription medications that were granted approval by the US Food and Drug Administration and for many years, have been used as appetite suppressants for short-term or for several weeks use only.  Phentermine was given approval in 1959 and fenfluramine was approved in 1973. Dexfenfluramine or in the form of Redux was granted approval in 1996 as an appetite suppressant for obesity management.

In 1990, several doctors started to prescribe fenfluramine or dexfenfluramine in combination with the phentermine for weight loss program and for extended period of use. The use of drugs in other ways or against what has been approved by the FDA is known as “off-label use.” With fen-Phen and dexfen-phen, there were no studies submitted to FDA to show either the effectiveness or safety of the drugs used in combination, hence, the use of these drugs in combination have not been given approval from the US FDA.

Fenfluramine and Dexfenfluramine Recalled from Market

US FDA has ordered the manufacturers to withdraw dexfenfluramine and fenfluramine from the market in September 1997. Dexfenfluramine was produced for Interneuron Pharmaceuicals and was distributed under the brand name “Redux” by Wyeth-Ayerst Laboratories which is a subsidiary of American Home Products Corp in Madison NJ. Thy also produced and distributed fenfluramine under the brand name “Pondimin.” These companies agreed to with draw their products voluntarily. However FDA did not ask the recall of phentermine which was the third famous for obesity treatment.

The withdrawal request of the FDA was after the echocardiogram testing of fen-phen patients recommended that fenfluramine and dexfenfluramine could have been the cause of heart valve problems.

FDA has recommended on September 15, 1997 that patients who were using either  of these products to discontinue taking them and asked the patients to contact their physicians to discuss their medications.

Studies Showed Heart Valve Problems

It was in July 1997 when researchers at the Mayo Clinic and Mayo Foundation submitted 24 cases of uncommon valvular illness in women who used the “fen-phen” combination therapy. Much later, FDA also received additional 66 cases of heart valve illness associated with “fen-phen” combination. Other reports showed cases in patients who took only fnefluramine or dexfenfluramine.

Take note that the human heart has four main valves that regulate the flow of the blood through the heart, then to the lungs and in general circulation. The illness may lead to extreme tightness or stenosis or leakiness or “regurgitation” of the valves. With valve disease linked with fenfluramine and dexfenfluramine, the leakiness is the problem. The valvular injury may result to severe heart and/or lung diseases.

Heart Risks Associated with Fenfluramine and Dexfenfluramine

For patients who have used fenfluramine and desfenfluramine may experience changes in their heart valves that result leakiness and backflow of the blood. If this is chronic, the heart must work harder and later may cause heart function problems.

The patients may have no symptoms but the doctors may hear new heart murmur, which may sound as the blood flows over a valve. The changes may also be observed with painless and non-invasive special heart exam which is known as echocardiogram. Echocardiogram is performed by a cardiologist. If the case is severe, the patient may suffer symptoms such as shortness of breathing, extreme exhaustion, chest pain, fainting, and swelling of the legs or edema.

Legal Cases on Fen-Phen

When the fenfluramine and dexfnfluramine were recalled from the market, there were hundreds of former fen-phen patients who filed legal cases against the drug manufacturers which includes a countrywide class suit that was settled and has received a judicial approval in January 2002.

Hence, if you or any of your family members have experienced disease as a consequence of Fen-phen use, your rights may be affected by the countrywide class action or by some legal proceedings which are associated to Fen-phen. However, you are entitled to file your case for any harm caused by Fen-phen drug use, particularly if your heart problems were discovered just recently. The best way to make sre that your legal rights are safe is to contact an experienced lawyer who will discuss your case and your legal options.

Would you like to discuss your legal matter?


image description
Jack Morgan CALL US! 866-205-4971

We will assist in scheduling new and existing clients for all offices. For initial consultations we will ask you a few questions and then find the best time for you to talk to one of the lawyers that best fits your legal matter.

Call us or use the email form and we will follow up with you right away.


The Law Offices of Hogan Injury will provide you with personalized attention and guidance. Protecting your rights is our main objective. We have been representing clients for the past 30 years and our experienced team of attorneys will advise you of the legal consequences of every decision you take.