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Dexfenfluramine is the first new anti-obesity drug to be approved by
the FDA in 23 years. Although the drug was just recently recommended by
an advisory panel for sale in the U.S. by a narrow 6 to 5 margin, it has
been available in Europe for the past decade and it is sold in 65 countries
It is being marketed under the name "Redux" and its purpose is
to help people lose weight by suppressing appetite.
Redux is appropriate for people with a BMI (body mass index) of at least
30, or someone who is 30 percent over his ideal body weight. For example,
if a 170 pound woman has an ideal body weight of 130, then she is a candidate
for Redux. It may also be prescribed to someone with a BMI of 20 or greater
in the presence of other risk factors (hypertension, diabetes, or hyperlipidema).
Denfexfluramine should not be prescribed for or taken by anyone who casually
wants to lose 10 or 15 pounds (http://www.pharminfo.com/pubs/msb/dexfen2.html).
Redux, which from this point on will be referred to as denfexfluramine,
is taken in the form of two 15 milligram capsules daily at the cost of
approximately $2.40. The drug works by convincing the brain that the stomach
is full. Denfexfluramine triggers the release of serotonin in the brain
which depresses appetite and calms anxieties. Patients will eat smaller
than normal size meals without feeling hungry, thus aiding them in their
quest to lose weight. The drug is designed to be taken in conjunction with
a reduced calorie diet to maximize its benefits. Deborah Wesley, a Redux
user, attests to its effectiveness. "Once you take the pill and you
sit down to the table all those cravings and those urges for out the window.
You start to eat and you feel full really quickly" (http://www.wraltv.com:80/features/healthteam/1996/1106-weight-partl/html).
Weight loss with denfexfluramine appears to be relatively modest for most patients. In addition, the majority of weight loss occurs within four to six months of initiating use, with weight loss declining after this period. If no weight loss occurs after one month of use, the patient and doctor must re-evaluate this drug therapy..
There have been several studies which attempt illustrate the potential
weight loss for denfexfluramine users. Interneuron Pharmaceuticals of Lexington,
Massachussettes reported that denfexfluramine helped 40 percent of people
studied lose up to 10 percent of body weight -- double the amount of weight
lost through diet alone (Seachrist 358). In a three month placebo controlled
study, obese patients taking the recommended dosage of denfexfluramine
(30 milligrams daily) lost weight and reduced blood pressure. This drug
therapy appears to reduce cardiovascular risks as well as reducing obesity.
Other claims have been presented about denfexfluramine. one states that the drug is not known to be addictive. However, no studies have been carried out longer than one year, and therefore this claim is not well-researched. In addition, denfexfluramine is not an amphetamine, but it can give its user a false positive urine test for amphetamines. The FDA has not set any limits regarding long-term usage.
Information about denfexfluramine is widespread, and it is put forth
by a variety of sources. One study which praises the effectiveness of denfexfluramine
for weight loss was funded by Wyeth-Ayerst, a company which stands to make
large profits from the advent and proliferation in the sales of Redux.
There are also many science bulletin pages which post pro and con information
concerning a variety of issues, educating the public. In addition, the
sale of denfexfluramine is a popular topic with journalists. Obesity, weight
loss, and diets are a growing focus of our culture and therefore they are
more prevalent in the media.
Scientific studies of denfexfluramine have demonstrated that increased weight loss is seen in patients who take Redux in conjunction with dieting as opposed to dieting alone. In the previously mentioned study by Wyeth-Ayerst, in 16 of 17 trials patients lost and kept off significantly more weight when treated with denfexfluramine as opposed to a placebo. All patients were on a 1200-1500 calorie a day diet. In one large trial of 930 patients followed for up to one year, 64 percent, 40 percent and 21 percent of those taking denfexfluramine lost at least 5 percent, 10 percent or 15 percent, respectively, of body weight by the close of the study. These numbers can be compared to 43 percent, 21 percent, and 10 percent of subjects who lost weight while only taking the placebo (American Journal of Nursing 56).
Another study, performed at the University of Amsterdam, the Netherlands, failed to replicate these same results. They concluded that denfexfluramine did not demonstrate an effect on diet composition (and therefore weight loss) for those who did not crave carbohydrates (binges), who were under strict dietary guidance, or those who did not have free food choices. However, denfexfluramine enhanced subjects dietary compliance and reduced preoccupation with food, although this was not necessarily reflected in weight loss. This interesting finding should lead doctors to investigate what types of patients could benefit from the anxietyreducing effects of denfexfluramine (Mathus-Vliegen and Res 1165).
Although research has demonstrated that there appear to be benefits
for some obese patients who take denfexfluramine, there has been literature
published about the possible risks of this diet pill. The risks range from
mild side effects to more serious serotonin syndrome, brain damage, and
primary pulmonary hypertension (PPH). Many doctors as well as HRG (Public
Citizens Health Research Group) are striving to make their voices heard
about the dangers of denfexfluramine.
Common negative effects of denfexfluramine are diarrhea, asthenia, dry
mouth, somnolence, dizziness, abdominal pain, and thinking abnormalities.
The drug may also enhance the effect of alcohol or other medications which
act on the central nervous system. In addition, a patient can experience
insomnia, fatigue, general weakness, and headache if he discontinues the
use of Redux (http://www.pharminfo.com/pubs/msb/redux.html).
Yet it has been the more serious risks which have caught the attention
of people within the medical community. In the Journal of the
American Medical Association, there was concern expressed for serotonin
syndrome associated from denfexfluramine use. This can occur when two serotoninergic
agents (such as denfexflnramine and anti-depressants) are being taken by
a patient at the same time. This combination can cause disorientation,
agitation, tremors, fever, shivering, diarrhea, coma or possibly death.
Stringent labeling must be applied to all drugs so that this costly error
will not occur (Schenck and Mahowald).
Denfexfluramine has also sparked a debate as to its neurotoxicity. "Denfexfluramine has a propensity to damage serotonin neurons," says George Ricaurte, MD, Ph.D., assistant professor of neurology of Johns Hopkins School of Medicine, Baltimore, MD. In his research Ricaurte gave denfexfluramine to monkeys, up to 20 times the prescribed amount per day for four consecutive days. When he studied the monkey's brains a year and a half later he discovered significant damage to the endings of nerve cells that release serotonin. He also added that denfexfluramine remains in humans seven times longer than it does in animals, and over time damage might occur. Damage can be manifested in patients as mood or sleep disturbances (Voelker 1087).
But denfexfluramine also has its supporters, such as Richard J. Wurtman,
MD, the Cecil H. Green distinguished professor of neuroscience at the Massachussettes
Institute of Technology (MIT), the man behind Redux in the United States.
"There is zero neurotoxicity," he states. "If something
clinically significant were going on, we would have know it because millions
are taking it." Wurtman asserts that damage is only shown when animals
are given megadoses of medication. In addition, he claims that the serotonin
depletion caused by denfexfluramine is not an indicator of neurotoxicity,
it is merely "interesting" (Voelker 1087).
The final and most serious risk of denfexfluramine being investigated
is primary pulmonary hypertension (PPH). With this condition, the blood
vessels that feed into the lungs constrict and the heart must work harder
to get blood through the tightened vessels. This increased strain can make
the heart fail, and it can be fatal (Fraser 57). Symptoms of PPH include
shortness of breath, chest pain, fainting, and swelling of legs, ankles,
or feet. In a two year, five country study, researchers in Canada and Europe
compared 95 PPH patients to 355 controls matched for age, sex and number
of visits to a physician. Thirty-two percent of PPH patients admitted to
using appetite-suppressant drugs before being diagnosed, as compared to
seven percent usage by control subjects. Researchers concluded that using
appetite suppressing drugs for longer than three months was associated
with 23 time greater risk of PPH (American Journal of Nursing 56). Overall,
PPH is still extremely rare with only 18 cases per million in denfexfluramine
users as opposed to one to two cases per million in the general population
(Barnett 1321) (http://www.rxlist.com/cgi/generic/dexfen.htm).
The benefits and risks must be carefully evaluated for each person who is contemplating the use of dexfenfluramine. One essential point is that the drug can only regulate hunger, and not everyone eats because they are hungry. Emotional overeating can not be controlled by Redux. But more fundamentally, one must ask the question of which risks are greater: the risks that denfexfluramine presents, or the risk of maintaining an obese state? Obesity is the second leading cause of death in the United States, second only to smoking (Sternberg 134). Therefore, the problem of obesity can not be taken lightly. There is no right or wrong answer about Redux as a treatment for obesity. It continues to be evaluated by researchers and patients alike who are looking for a safe and effective tool for reducing the problem of obesity.
Barnett, A. A. (1996). New obesity pill approved by FDA. The Lancet,
Dexfenfluramine: Growing market seen for reducing drug. Ainerican
Journal of Nursing (1996), 96, 56-58.
Fraser, L. (1996). The New Diet Drugs. Health, 52-57.
Mathus-Vliegen, L. and Res, A. (1993). Dexfenfluramine influences dietary
compliance and eating behavior, but dietary instruction may overrule its
effect on food selection in obese subjects. Journal of the American
Dietetic Association, 93, 1163-1165.
Schenck, C. and Mahowald, M. (1996). Potential hazard of serotonin syndrome
associated with dexfenfluramine hydrochloride (redux). Journal of the
American Medical Association.
Seachrist, L. (1995). Panel OK's diet drug. Science News, 148t
Sternberg, S. (1996). Weight loss pills linked to lung ailment. Science
News, 150, 134-135.
Voelker, R. (1994). Obesity Drug Renews Toxicity Debate. Journal
of the American Medical Association, 272, 10871088.
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