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Is It Safe to Take Fen-Phen?

This article concerns the prescribing in combination of two anorexic (appetite suppressing) drugs, Fenfluramine [fen] and Phentermine [phen], which separately have been on the market since the 1970s. Physicians became interested in combining the medications following the 1992 publication of a University of Rochester study conducted by Dr. Michael Weintraub wherein he described long-term successful weight loss results when combining the two medications. Fen had always been known to have an appetite suppressing effect, but had the undesirable side effect of making people sleepy. The gist of combining the drugs was to counterbalance this sleepiness by adding phen, a mild stimulant. The drugs are marketed under the catch phrase "fen-phen". The drugs were prescribed to 18 million people last year. The Wall Street Journal reports 18 million fen-phen prescriptions a month in 1996.

It is estimated that 58 million Americans are clinically obese, those with a body weight 20-30% above normal. Obesity results from a complex interaction of genetic, behavioral and environmental factors, is the second leading cause of preventable death in the United States, and is a major cause of premature mortality. Obesity is difficult to treat and brings along the associated health problems of high blood pressure, diabetes, cardiovascular disease, and high cholesterol, all of which can lead to heart attacks. Thus, it is no wonder that diet medications which are safe and effective would be in high demand.

The idea of marketing safe drugs to reduce excess weight is a relatively new phenomenon, since diet pills in the past have been synonymous with amphetamines, conjuring up, an image of sleazy feel-good doctors getting patients hooked on "speed". Amphetamines, producing central nervous system stimulation, were originally used in the treatment of narcolepsy and to combat mental depression, and only later were tried for appetite control and in the treatment of obesity. The use of amphetamines to control appetite in treating obesity has not over the long term proved to be effective. Large doses of amphetamines are toxic and prolonged use may cause drug dependence. Fen's pocket insert advises that it is a controlled substance, related chemically to the amphetamines, and drug dependence should be kept in mind when evaluating the desirability of including the drug in weight reduction programs of individual patients. Until recently, the national weight problem has been addressed by Americans spending an estimated 33 billion dollars annually on diet books, joining health clubs, and eating low calorie foods. Unfortunately for many, these ideal remedies, based upon exercise and character-building restraint, have not worked. And so a cross-section of Americans, from those who just want to be cosmetically thin to those with a serious morbid obesity problem, have longed for a drug or a combination of drugs which could be prescribed by their physician and which would be both safe and effective in the long run.

The Mechanism of Weight Loss

The non-obese person maintains normal weight without drugs. In a nutshell, the normal person experiences a sense of fullness which provides physical and emotional well being after eating. Simply stated, the body knows when to say "I have had enough". Scientific study has established that these feelings of satisfaction occur when certain neuro-transmitters in the brain, molecules of serotonin, are released. Fen-phen stimulates the brain to release an EXTRA amount of serotonin. Science reasons that if serotonin brings satisfaction to the normal eater, then an extra amount of serotonin will quicken the ending of the obese person's desire to eat. With appetite reduced, over time, significant and lasting weight loss should occur, or so goes the argument.

Risks Associated with Fen-Phen

Concerns about the side-effects of fen-phen have increasingly become the focus of media attention and a source of worry in the medical community. On July 8, 1997 CNN reported information about an article to be published August 27, 1997 in the New England Journal of Medicine revealing that 24 midwestern women have developed heart-valve disease as a direct result of using fen-phen diet pills. Pre-publication release of information about a medical article is unusual, reserved for only the most serious public health matters, and highlights the urgency of the problem. Prior to this announcement, fen-phen's most serious known side-effect was primary pulmonary hypertension (PPH), a serious and potentially-fatal disorder in which the arteries supplying the heart are constricted, producing abnormally high blood pressure, shortness of breath and fatigue. European research into fen-phen reveals that those using these drugs for more than three months increase their risk of PPH from the normal 1 or 2 in 1 million patients to 18 in l million. Other studies suggest the risk is 43 in 1 million. According to the Journal article, fen alters serotonin metabolism in the brain while phen interferes with the pulmonary clearance of serotonin in the blood stream, which may explain its association with PPH. Significantly, the Journal article, states the association of valvular problems with fen-phen is not likely due to chance and that candidates for the fen-phen drug therapy should be informed about this serious potential adverse side effect.

The FDA Response

The FDA sent a letter on July 8, 1997 to thousands of doctors asking them to immediately find out if their fen-phen patients have experienced symptomatology suggestive of a heart valve problem. When untreated, valve problems can lead to congestive heart failure. Valve damage causes blood to leak back into the heart, making the heart work harder.


Redux is a single capsule prescription drug containing a refined version of fen-phen and was popularized in September 1996 when Time magazine ran a cover story on the hot new diet pill. Further notoriety came with publication of a book - The Redux Revolution: ›Everything You Need to Know About the Most Important Weight Loss Discovery of the Century. Sheldon Levine, its author, proclaims "what makes Redux revolutionary is that it restores confidence in one's own self-control".

Redux FDA Approval?

While fen and phen are prescription drugs separately approved by the FDA, only the Redux form of fen-phen has received FDA approval. Individually, fen and phen were approved by the FDA for short term use only, while the combination fen/ phen was approved for long term use in order to maintain weight loss. Further, the FDA advised Redux was only to be prescribed to those who have been diagnosed as obese (in adults a body mass index greater than 27.8 kg/2m and in females greater than 27.8 kg/2m and in conjunction with diet and exercise. However, critics like Lewis Seiden, a pharmacologist at the University of Chicago, and others question the FDA approval process, claiming that the FDA "glossed over evidence that both Redux and the older drug fen cause significant brain damage in laboratory animals". Originally, the FDA advisory committee rejected Redux on safety grounds by a 5-3 vote. Later, Redux obtained FDA approval by a one-vote margin.

Other Responses

The French Government has restricted the use of Redux to the morbidly obese after it was discovered there were an estimated 20 deaths a year associated with Redux. The state of Tennessee has altogether banned the sale of fen-phen.

Legal Liability

Physicians who prescribe fen-phen should realize the potential of liability exposure. Physicians and the public should be aware that the combination fen-phen (apart from Redux) is a drug which has not undergone FDA testing (animal and clinical studies on humans) and therefore the utmost care and consideration should go into the decision-making process of whether to prescribe the drug. After prescribing the drug, physicians must supervise the patient carefully to determine if there are any developing cardiopulmonary side effects, to make sure the fen-phen drug therapy is working: weight loss with safety.


In light of the information set forth in this article, a jury might conclude that a defendant-physician, manufacturer, or weight loss clinic failed to adequately warn a patient, failed to gain the informed consent of a patient, misrepresented the safety of fen-phen, mistakenly prescribed fen-phen in the first place, or failed to supervise the care of the patient during drug therapy.

This informational piece was prepared by Silverman & Fodera. If you would like more information on this topic, call us at (800) 220-LAW1, or use the "Do I Have A Case?" link on this web site.