DIET PILLS

Official Drug Name: 
benzphetamine (Didrex),
diethylpropion (Tenuate, Tenuate Dospan), orlistat (Xenical),
phendimetrazine (Bontril),
phentermine (Adipex-P, Ionamin), sibutramine (Meridia)

Drug Classifications:
Schedule III
(benzphetamine and phendimetrazine),

Schedule IV (diethylpropion, phentermine, and sibutramine); stimulants.

What Kind of Drug Is It?

Prescription diet pills are stimulants—substances that increase the activity of a living organism or one of its parts. Diet pills that can only be prescribed by physicians fall into one of two categories: 1) appetite suppressants; or 2) lipase inhibitors. Lipase is a substance that speeds up the breakdown of fats in the body. Appetite suppressants, also known as ANORECTICS, decrease feelings of hunger. These drugs were created to replace AMPHETAMINES, which proved to be an extremely dangerous method of weight control.

Overview

The obsession with thinness seen throughout Europe and North America in the twentieth and early twenty-first centuries is a trend that developed during the late 1800s. The concept of beauty prior to that time was completely different. In fact, a full figure for women was actually quite desirable. Art from the 1700s and 1800s depicts women as well-endowed, curvaceous, and quite proud of their bodies. A few extra pounds on an individual were considered a sign of good health and high economic status. Fine French chocolates were all the rage among the rich, while the less fortunate and painfully thin lower classes barely had enough food or money to sustain themselves.

Early Diet Pills

By the late 1800s, however, attitudes about weight were beginning to change, especially among women. The first diet pills, referred to at that time as "fat reducers," showed up on the market in 1893. These pills were thyroid extracts. The thyroid is an important gland in the body. It secretes chemical messengers called hormones that control metabolism. Metabolism is the process by which food is converted to energy that the body uses to function. Thyroid extracts are used to correct problems with the thyroid gland. Their use causes people to lose weight, but produces dangerous side effects in people with normal thyroids. These effects include muscle weakness, chest pains, an increased heart rate, abnormal heart rhythms, high blood pressure, and even death. Despite the risks, overweight people continued to seek out the thyroid hormone as a weight-loss remedy until the 1950s.

The "New" Drug of the 1930s: Dinitrophenol

"Weight-loss pills in general have a rather alarming history," wrote Denise Grady in the New York Times. In 1933, a drug called dinitrophenol (DY-NY-troh-FEE-noll) went on the market. It became a popular weight-loss remedy, despite the fact that it was originally used as a PESTICIDE. "During the 1930s," noted Grady, "about 100,000 Americans took ... dinitrophenol, which prevented food energy from being turned into fat." But the drug turned out to be poisonous for humans as well as pests. It caused damage to the taste buds, blindness, serious skin rashes, extremely high fevers, and even death. Dangerous and sometimes fatal side effects associated with drugs like dinitrophenol led the U.S. Congress to enact the Food, Drug, and Cosmetics Act in 1938. The act gave the U.S. government powers to regulate substances marketed as drugs. However, some people still managed to purchase dinitrophenol through mail-order companies through the 1940s.

From Dinitrophenol to Amphetamines to "Amphetamine-Like" Diet Drugs

The use of dinitrophenol dropped as dieters discovered amphetamine, a medication developed in 1887. Historically, doctors prescribed amphetamines as an appetite suppressant. Amphetamines tend to decrease feelings of hunger in people who take them, making them an often-abused drug among dieters. Although the use of amphetamines for weight control was popular in the 1950s and again in the 1980s and part of the 1990s, this practice is no longer very common. Amphetamine use for weight loss is dangerous because it can become addictive. Some overweight individuals may resort to illegal means to obtain prescription-only amphetamines and even methamphetamine. Most doctors agree that the best way to regulate weight is through moderate exercise and a healthy diet. The dangers of amphetamine addiction prompted drug companies to develop "amphetamine-like" diet pills—medicines containing chemicals similar to amphetamines. Although not quite as powerful as amphetamines, these pills did reduce users’ appetites and were considered safer, with less potential for misuse or abuse.

Into the Twenty-first Century

As of 2005, "in weight-obsessed America... two-thirds of adults are overweight or obese," wrote the authors of an MSNBC.com article on fitness. In the same article, Dr. JoAnn Manson, chief of preventive medicine at Boston’s Brigham and Women’s Hospital, stated: "A prescription for exercise may be the most important prescription a physician writes all day." Dozens of prescription diet pills have come and gone over the years. A large number of them are no longer available for use by patients. Physicians can no longer write prescriptions for them because they have been "discontinued." As of 2005, according to the FDA, approximately twenty-five prescription diet pills had been categorized as "discontinued." A discontinued drug product is one that has been removed from the market in the United States for reasons other than safety or effectiveness. The exact reason or reasons for their removal are not stated on the FDA Web site. The large number of these drugs only serves to highlight America’s cultural obsession with weight.

What Is It Made Of?

Most diet pills are SYMPATHOMIMETICS, or amphetamine-like drugs. They stimulate the sympathetic nervous system in a way similar to amphetamines. The sympathetic nervous system is responsible for the body’s "fight or flight" responses in the face of danger. The body releases a burst of energy that increases blood pressure, makes the heart beat faster, and slows digestion. These types of actions decrease hunger in users. Diet pills included among the sympathomimetics are benzphetamine, diethylpropion, phendimetrazine, and phentermine. Orlistat is a lipase inhibitor. Lipase is a substance that speeds up the chemical breakdown of fats. By "inhibiting" the action of lipase, orlistat blocks fat absorption in the intestine. An estimated 30 percent of fat that would normally be absorbed by the intestines is allowed instead to pass right through the body undigested.

How Is It Taken?

The weight-loss medications described in this entry cannot be dispensed without a doctor’s prescription. They are manufactured in both pill and capsule form and are taken by mouth. The patient follows a dosage schedule set by the physician. Most prescription diet pills are taken before meals to take the edge off a person’s hunger.

Are There Any Medical Reasons for Taking This Substance?

Prescription diet pills are not recommended for people who are only slightly overweight. These drugs are used to treat obesity, a medical condition characterized by excess fat stored in the body. People who are considered overweight or obese weigh more—generally 20 percent or more—than is considered healthy for their heights and ages. Obese people are at risk for such medical conditions as DIABETES, STROKE, and heart disease. Obesity contributes to the deaths of about 300,000 Americans annually,
according to the FDA.

Body Mass Index

A more specific standard called body mass index (BMI) is used to determine whether an overweight or obese individual is a candidate for prescription diet pill therapy. Body mass index is a calculation that expresses the relationship between a person’s weight and height in a single number. It is used as an indicator of health risk due to excess weight. Diet drugs may be prescribed to a person with a body mass index (BMI) of at least 30 and no medical conditions related to obesity. A BMI of 30 is assigned to a 5-foot-5-inch-tall (1.65-meters tall) person weighing 180 pounds (81.65 kilograms), a 5-foot-7-inch-tall (1.7-meters tall) person weighing about 190 pounds (86.18 kilograms), and a 6-foot-tall (1.83-meters tall) person weighing about 220 pounds (99.79 kilograms).

Length of Treatment

The biggest problem with prescription diet pills is that some users develop a dependence on them. Most diet pills are prescribed for short-term use, which ranges from a few weeks to several months. The goal of this treatment is for patients to lose weight at a steady rate and keep the weight off. Diet pills are only part of the treatment that focuses on changing patients’ behavior. These changes generally consist of establishing and sticking to an exercise routine as well as following a healthy diet.

Effects on the Body

The diet pills developed to replace amphetamines became known as anorectics or appetite suppressants. Anorectics are sometimes referred to as sympathomimetic drugs. They are stimulants that "mimic" the body’s natural energy-releasing mechanisms. The FDA has approved a variety of anorectics over the years for the shortterm treatment of obesity. Phentermine was approved in 1959, fenfluramine (FENN-FLOOR-uh-meen) in 1973, and dexfenfluramine (deks-FENN-FLOOR-uh-meen) in 1996. Other anorectic diet pills include benzphetamine, diethylpropion, and phendimetrazine. A different type of prescription diet pill received FDA approval in 1999. The lipase inhibitor orlistat (Xenical) is said to block about 30 percent of the fat absorbed by the body.

The Fen-Phen Craze

In the 1990s, doctors in the United States and other countries began prescribing low doses of fenfluramine (Pondimin) or dexfenfluramine (Redux) along with low doses of phentermine. The combination, known informally as "Fen-Phen," was never approved by the FDA. Seven million prescriptions for Fen-Phen were written in 1996. "The rationale for using the two drugs," according to a Seattle Times contributor, "was that they might work more effectively together with fewer side effects." Soon, however, the safety of Fen-Phen was called into question. The appetite-suppressant mixture was thought to be the cause of some severe health problems, including serious heart valve malfunctions. As a result, both fenfluramine and dexfenfluramine were withdrawn from the market in September of 1997. Phentermine is still sold because no cases of heart valve disease have been reported when that drug is taken alone, according to an FDA report.

There Are No Magic Cures

Prescription diet pills help with weight reduction by suppressing the user’s appetite and increasing the feeling of fullness in the stomach. But diet pills alone will not make excess weight disappear. According to Patricia Dwyer Schull in the Nursing Spectrum Drug Handbook, prescription drugs for "obesity management" must be "used in conjunction with [a] reduced-calorie diet" in order to be effective. Diet pills can produce symptoms that range from dizziness to an increased number of bowel movements. Possible side effects include light-headedness, dry mouth, a false feeling of well-being, nausea, irritability, INSOMNIA, trembling, blurred vision, nervousness, increased sweating and urination, and problems with the blood vessels in the lungs. Sibutramine (Meridia), a prescription diet pill approved by the FDA in 1997, may cause an increase in heart rate and blood pressure. Long-term use of any prescription appetite suppressant can lead to addiction. Taking anorectics can impair a person’s ability to drive, operate heavy equipment, or perform other potentially hazardous activities. Sympathomimetics or anorectics should not be prescribed to people with a history of drug abuse.
Taking orlistat, the lipase-inhibiting-type diet pill, can bring on an increased number of bowel movements, gas with discharge, oily or fatty stools, and the inability to control a bowel movement. Because orlistat blocks the absorption of fat in the intestines, the fat is eliminated from the body as part of a bowelmovement. Orlistat users may sometimes feel an urgent need to go to the bathroom. These symptoms are often aggravated if the user eats too many high-fat foods. Women who are pregnant or nursing their babies should consult with their physician about any diet pill use. Most prescription diet pills are not recommended for use by pregnant or nursing women. Diet pills can also affect bone development in children and young adults. When patients stop taking anorectics, their bodies need to adapt to the lack of drugs in their systems. The amount of WITHDRAWAL time will vary, depending on the strength of the dosage taken and the length of time it was used. Withdrawal symptoms may include insomnia,
nightmares, nausea, vomiting, and stomach cramps. The user typically experiences strong hunger pangs as well.

Possible Dopamine Connection

A study conducted by the National Institute on Drug Abuse (NIDA) suggests that the same factors that control excessive behaviors such as drug abuse and gambling may be associated with overeating. The main factor may be an abnormality in the brain involving chemical messengers called NEUROTRANSMITTERS. DOPAMINE is the neurotransmitter that acts on the part of the brain responsible for feeling pleasure, filtering incoming information, making choices, judging behavior, and deciding when and how to act. NIDA researchers believe that obese people do not have enough receptors on their brains’ nerve endings to grab on to dopamine and allow it to do its work. The decrease in dopamine receptors is apparently linked to a high BMI. The greater a person’s BMI number, the fewer dopamine receptors they seem to have in their brains. NIDA Notes staff writer Robert Mathias quoted Dr. Nora Volkow as saying: "An individual who has low sensitivity to normal stimuli learns behaviors, such as abusing drugs or overeating, that will activate" those areas of the brain that "create a sense of wellbeing." The next step in this research is to determine if there are ways other than overeating or drug-taking that can stimulate the pleasure centers in the brains of these individuals.

Reactions with Other Drugs or Substances

Before taking diet pills, patients need to inform their health care providers of any other medications they are already taking. Diet pills are often taken in combination with LAXATIVES, DIURETICS, and herbal remedies, which can lead to dangerous drug reactions. Mixing diet pills with alcohol can have serious side effects. In addition, certain antidepressants can interact negatively with prescription diet pills, causing high blood pressure or an irregular heartbeat. Physicians may decide to adjust drug dosages, have patients discontinue certain medications, or counsel the patient not to use prescription diet pills at all.

Treatment for Habitual Users

Since many of the prescription diet pills available to overweight patients are amphetamine-like substances, they tend to have the same effects on users as amphetamines. TOLERANCE to diet pills can occur if the user takes the drugs in a greater quantity or for a longer time than instructed. It is very important to remember that prescription weight-loss medications are meant to be used only for a limited time. If diet drug dependence or addiction does occur, experts consider behavioral therapy—sometimes referred to as "talk" therapy—and emotional support essential for treatment and rehabilitation. Treatment must be adapted to the individual. It should include nutritional counseling and advice on lifestyle changes that will help the patient reach and maintain a healthy weight.

Consequences

In a society where "thin is in" and people are often judged by their appearance, diet pill use has skyrocketed. However, diet pills are merely a temporary solution to a long-term problem. Maintaining a healthy weight is an ongoing process that involves adopting a whole new lifestyle of eating healthy meals and exercising regularly.

Diet Pill Abuse

People who use diet pills often put the pounds they have lost right back on as soon as they stop taking the drugs. Not only do they regain the weight they first lost, they sometimes gain even more. This process is called the "yo-yo syndrome" because the affected individual’s weight goes up and down like a yo-yo. Common consequences of diet pill abuse include muscle loss, psychological dependency, feelings of failure, and a generally unhealthy physical state. Overuse of pills can affect concentration and performance in school or work. In addition, there is a potential for addiction to some diet pills.

The Struggle to Be Thin

Although excessive weight and obesity are problems in the United States and other countries, there is also a concern about people who diet to an unhealthy low weight. Individuals suffering from eating disorders have an unrealistic image of themselves and their bodies. The most common eating disorders are ANOREXIA nervosa and BULIMIA nervosa. For someone with an eating disorder, taking diet pills can aggravate an already serious condition. If left untreated, eating disorders can be fatal.

The Law

The Food and Drug Administration (FDA) oversees the regulation of prescription diet pills. The Controlled Substances Act (CSA), a portion of the 1970 Comprehensive Drug Abuse Prevention and Control Act, classified drugs into five categories, or schedules, based on the effect of the drug, itsmedical use, and potential for abuse. Schedule I drugs, those in the most tightly controlled category, have no medical use and an extremely high potential for abuse. Among diet drugs, benzphetamine and phendimetrazine are considered Schedule III drugs. Abuse of these drugs may lead to physical or psychological dependence. Diethylpropion, phentermine, and sibutramine diet pills are considered Schedule IV drugs. They have a lower potential for abuse than the Schedule IIIs, but still may lead to physical or psychological dependence in some users. Federal law prohibits the use or distribution of diet pills obtained without a prescription.

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Health Risk Re-evaluated

In an interesting spin on the over-emphasis given to obesity in the United States, the Centers for Disease Control and Prevention (CDC) announced in April of 2005 that being "modestly overweight" might not be as dangerous as once thought. According to CNN.com, the CDC’s study revealed that "people who are modestly overweight have a lower risk of death than those of normal weight." The key term here is "modestly," meaning slightly. CDC director Dr. Julie Gerberding cautioned that severe obesity remains a major health risk but pointed out that the definition of obesity is evolving. The CDC’s new report changes obesity’s ranking among "the nation’s leading preventable causes of death" from number two to number seven, behind smoking, alcohol, germs, toxins and pollutants, car crashes, and guns. It could take awhile for the CDC’s new vision of a healthy weight to take hold throughout a weight-loss-obsessed culture. MSNBC.com reported that girls as young as nine years old are  "using bodybuilding steroids — not necessarily to get an edge on the playing field, but to get the toned, sculpted look of models and movie stars." Steroids aid in this quest by helping replace fat with muscle. In many cases, the girls taking steroids suffer from eating disorders such as bulimia and anorexia as well.

Diet Fads

Dieting has a long and somewhat curious history. The use of diet pills to lose weight began around the turn of the twentieth century and has carried over into the twenty-first. With the dawn of the 1920s, the ideal body type became a thin one (although not as extreme as the "model thin" type that started gaining popularity in the 1980s). Throughout the 1920s, new weight-loss trends developed. One was the use of laxatives—medicines that relieve constipation by loosening the bowels—to clean out the lower digestive tract. This can be a very risky practice, though, since overuse of laxatives can cause dehydration and chemical imbalances in the body. Laxative abuse continues to this day. Around the same time as the laxative boom began, other unusual weight-loss products hit the market. One of the best known was called La-Mar Reducing Soap. This product promised to "wash away fat and years of age",according to an advertisement from the London, England, soap manufacturer. Gimmicky weight-loss products continue to be marketed to people desperate to lose weight. Illegal Internet pharmacy Web sites started popping up in the 1990s, offering controlled substances for sale without a prescription. Another fad involved remedies that promised weight loss "without diet or exercise." Doctors caution patients against falling for scams like these.

New Obesity Drug

The quest for a better prescription diet pill continues. According to MSNBC.com, the drug company Sanofi-Aventis was seeking FDA approval in the spring of 2005 for a new obesity drug called rimonabant (RIMoh- NAB-ant), which was likely to be marketed under the name Acomplia. After extensive testing, rimonabant was found to help severely obese individuals keep off the weight they lost for up to two years. For long-term success, though, cardiologist Dr. Sidney C. Smith was quoted by MSNBC.com as saying: "There have got to be some improved behavioral and diet changes going on beyond taking a pill." Side effects of rimonabant in test users include nausea, dizziness, and increased cases of diarrhea. One unexpected effect: the drug may also help people stop smoking.

Eating Disorder Facts

Eating disorders are more common than most people realize and lead to a variety of health risks:
1. Close to 10 million women and 1 million men suffer from anorexia nervosa or bulimia nervosa.
2. Another 25 million people are affected by binge eating disorder.
3. Eating disorders can cause osteoporosis (the loss of bone mass).
4. Changes in the mouth and teeth are often the first signs of an eating disorder. Lips may look red, cracked, and dry, and teeth often erode (become brittle and weak) due to frequent vomiting and nutritional deficiencies.
5. If left untreated, eating disorders can be fatal.

By Barbara C. Bigelow, MAT, (Kathleen J. Edgar, Project Editor) in the book "Encyclopedia of Drugs & Addictive Substances", U.X.L an imprint of Thomson Gale, a part of the Thompson Corporation, 2006, excerpts vol.II p. 257-270. Adapted and illustrated to be posted by Leopoldo Costa.

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