What are the drugs used to treat excess weight?

 

A thorough account of the medications used for weight loss.

Well-Connected Report: Weight and Diet

The following excellent article about diet drugs appears at webmd.com

Drugs used for weight loss are generally called anorexiants. All the drugs are potentially effective when used appropriately and with additional weight loss measures, including exercise and behavioral modification. The long-term effects of most of these medications have not been established. Most lose their effectiveness over time, thus requiring increased dosage, and they can be addictive and dangerous. None of these drugs deals with the underlying problems that may be causing obesity. Unless specifically instructed by a doctor, people should use non-drug methods for losing weight. Except under rare circumstances, pregnant or nursing women should never take diet medications of any sort, including herbal and over-the-counter remedies.

Over-the-Counter Drugs and Herbal Remedies

People must be cautious when using any weight-loss medications, including over-the counter diet pills and herbal or so-called natural remedies. The following are examples of some being sold for weight loss.

Over-the-counter diet pills that contain phenylpropanolamine (Acutrim, Dexatrim) effectively suppress appetite, but have been known to cause severe high blood pressure and stroke if taken in doses of 75 mg or higher in the immediate-release form. The FDA has moved to take such products off the market.

A number of over-the-counter remedies (Herbal Phen-Fen, PhenTrim, Phen-Cal, Xenadrine) contain ephedrine, derived from the ephedra (also known as Ma Huang) herb. Ephedrine is actually a component in adrenaline and can cause a number of side effects, including infrequent cases of severe effects (rapid heartbeat, high blood pressure, psychosis, heart attacks and seizures). Pseudoephedrine, an ingredient commonly found in many antihistamines, has similar effects and is sometimes used by dieters.

There is some evidence that cholecystokinin (CCK), a protein derived from potatoes, may reduce appetite. A powder (Satietrol) is available.

Small studies on conjugated linoleic acid (CLA) suggest that it may reduce body fat and insulin levels in type 2 diabetics. Adverse side effects are frequent, however. Over-the-counter products containing tiratricol, a thyroid hormone, have been sold for weight loss. Such products may increase the risk for heart and stroke.

Many so-called natural remedies are being promoted for weight loss. Some can be dangerous and few have been tested. Chinese remedies that contain Aristolochia, for example, have been banned by the FDA after reports of cancer and kidney failure. Chitosan, a dietary fiber from shellfish does prevent a little fat from being absorbed in the intestine, but limited studies have not found that it contributes to weight loss. Garcinia (also called mangosteen) is a tropical fruit containing hydroxycitric acid, which is claimed to burn fat. Although theoretically promising, to date no well-conducted study has reported significant weight loss with the chemical.

Many dietary herbal teas contain laxatives, which can cause gastrointestinal distress, and, if overused, may lead to chronic pain, constipation, and dependency. In rare cases, dehydration and death have occurred. Some laxative substances found in teas include senna, aloe, buckthorn, rhubarb root, cascara, and castor oil. Some fiber supplements containing guar gum have also caused obstruction of the gastrointestinal tract.

Dietary remedies that list the ingredient plantain may contain digitalis, a powerful chemical that affects the heart. (This should not be confused with the harmless banana-like plant also called plantain.)

Orlistat

Orlistat (Xenical) can help about one third of obese patients with modest weight loss, and can assist in long term maintenance of weight loss. It reduces the body's absorption of fat from foods, thereby reducing weight and cholesterol. Orlistat blocks the action of lipase, an enzyme in the intestine that breaks down fat. It does not increase serotonin but it makes it work effectively, and it is a stimulant. Studies have found that at the end of the first year orlistat users achieve an average of 5% to 10% drop in body weight. Studies are also reporting that the drug may delay or prevent the onset type 2 diabetes, improve cholesterol levels regardless of weight loss, and reduce blood pressure. (It should be noted that some people who take this drug experience an increase in blood pressure.) The drug can cause gastrointestinal problems and may interfere with absorption of the fat-soluble vitamins A, D, and E and other important nutrients.

Sibutrimine

Sibutrimine (Meridia) keeps two important brain chemicals -- serotonin and norepinephrine -- in balance, which helps to increase metabolism. It causes a feeling of fullness and increases energy levels. Studies indicate that sibutramine assists with weight loss and helps maintain it. Patients who discontinue the drug, however, report significant weight gain afterward. Some studies also report improved cholesterol and other lipid levels with the use of this drug.

Common side effects include dry mouth, constipation, and insomnia. Of concern are reports of increases in heart rate and blood pressure, although on the positive side, two studies reported significant improvements in cholesterol levels. Experts believe sibutramine is probably safe, but the long-term effects are still unknown. People who have a history of high blood pressure, stroke, heart disease, or arrhythmias should not take this drug. People taking decongestants, bronchodilators (such as for asthma), monoamine oxidase inhibitors, or serotonin reuptake inhibitors should also avoid sibutramine.

Serotonin-Releasing Anorexiants

Serotonin-releasing anorexiants increase the availability of serotonin, a chemical in the brain that prevents depression and reduces calorie consumption. Unfortunately, the most popular of these drugs have very serious side effects, including development of abnormalities in the valves of the heart and, uncommonly, a potentially life-threatening condition called pulmonary hypertension. As a result, dexfenfluramine (Redux), fenfluramine (Pondimin), and the combination drug commonly called fen-phen, fenfluramine (Pondimin) have been pulled from the market. Studies report that changes may occur in patients taking the drugs for more than three months. To date, even in these patients, there do not seem to be serious complications. Taking the drugs for a short period (two to three months) appears to do no harm at all. Patients who were treated with Redux, Pondimin, or phen-fen for more than three months should have a thorough cardiovascular exam, including an echocardiogram. Many women who had valvular abnormalities had been taking multiples of the recommended dosages. Others were also on Prozac, an antidepressant that also increases serotonin and intensifies the effects of the diet drugs.

Amphetamines

The amphetamines dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), and phenmetrazine (Pleudin) were used most often in the past but are no longer prescribed for weight loss. These drugs elevate mood and produce some modest weight loss over the short term, but present serious risks of addiction, agitation, and insomnia.

Sympathomimetics

Sympathomimetics are agents that act like the neurotransmitter norepinephrine (a stress hormone). Less addictive and possibly safer than amphetamines, these drugs still raise blood pressure. They are approved for short-term use and include phentermine (Ionamin, Adipex, Fastin), diethylpropion, mazindol (Mazanor, Sanorex), benzphetamine (Didrex), and phendimetrazine (Adipost, Botril, Melfiat, Plegine, Prelu-2, Statobex). Phentermine has been withdrawn from the UK market but not the US.

Experimental Therapies

Naltrexone. The drug naltrexone (Trexan) blocks the euphoria of drug abusers and is being tested for people who binge. Its effects have been promising. (The drug has no effect on people who do not binge.) It is, unfortunately, available only by injection.

Leptin. Preliminary results from early studies on the use of daily injections of genetically engineered leptin are reporting weight loss among some genetically obese subjects. Higher doses may be needed for higher weights. The most common side effects were pain at the injection site and headache. There appear to be no significant adverse effects on major organs, including the heart, liver, kidney, central nervous system, or gastrointestinal tract. It also does not appear to affect insulin levels, a previous concern.

Neuropeptide Y. Neuropeptide Y is a powerful appetite-stimulating chemical in the brain. Agents are being investigated that block this peptic.

Accomplia

The hot new diet drug in the news is the French drug called Accomplia Rimonabant. It was created to help people quit smoking and lose fat by blocking circuitry in the brain that gives the body cravings.

The diet drug, rimonabant accomplia, which could be available in a year or two, is an appetite suppressant, but works by an entirely new approach by blocking the same primeval circuitry in the brain that gives pot-smokers the munchies. The French firm Sanofi-Synthelabo plans to seek U.S. approval to sell it under the brand Accomplia after more studies are finished next year.

Commentary: The bottom line with diet pills and supplements is that they have side-effects which make taking them in the long-term unreasonable. Quit taking them and the weight almost always comes back. There is the problem. If any diet pills worked in the long-term they would be sold by giant pharmaceutical companies, not multi-level marketing companies, midnight infomercials and obscure websites. With the epidemic of obesity in the United States they would be impossible to avoid in our society and would be front page news.

Related

Dietary Supplement Health and Education Act of 1994
The Bottom Line about Diet Pills