We spend almost $60 billion a year trying to lose weight. We join gyms and sign up for programs like Jenny Craig. We buy diet books, foods, drinks and supplements, and even have surgery. So isn't it strange that we only spent about $173 million on prescription weight loss drugs in 2008?
It's not that we wouldn't spend more. A safe prescription drug that could make us slim would be a blockbuster. But so far, we don't have one. Only two prescription long-term weight loss drugs are approved by the FDA. Both have modest effects on weight, and side effects many of us can't tolerate.
What weight loss drugs are government-approved?Two prescription drugs are approved. But your health care provider won't prescribe them just so you can drop a few pounds. They're meant for people who:
- Have tried to lose weight in other ways without success
- Have a body mass index (BMI) over 30
- Have a BMI over 27 and a medical condition like diabetes, high blood pressure, high cholesterol, heart disease or sleep apnea
You should exercise regularly and eat a low-calorie diet while taking either medication.
- Orlistat (Xenical) works by keeping your intestines from absorbing some of the fat in foods you eat. You take it with or soon after meals. Orlistat blocks absorption of fat-soluble vitamins A, D and E. So you also need a daily multivitamin at least 2 hours before or after you take this medicine. Diabetics should talk to their providers before use. Orlistat can affect your blood sugar level and change the amount of diabetes medicines you may need.
Many of the common side effects are gastrointestinal. They include oily spotting on underwear, gas, urgent or frequent need to move your bowels, fatty or oily stools, loss of control of bowel movements, stomach pain, rectal pain, and nausea. A low-fat diet may decrease these symptoms. Headache, stuffy nose, back pain, irregular periods and fatigue have also been reported.
The FDA is also investigating some reports of liver damage in people who've taken orlistat. We don't know if the drug caused it or it was coincidental. But the FDA warns orlistat users to look out for yellowing of the skin or whites of the eyes, weakness, stomach pain, fatigue, fever, or brown urine.
Alli is a lower-strength over-the-counter version of orlistat. It's approved for sale to overweight adults 18 years and older. Side effects like diarrhea and gas are common with Alli, too. - Sibutramine (Meridia) is an appetite suppressant that affects the brain. It's prescribed for weight loss and to prevent regain. There's a long list of contraindications. Many are conditions you might have that usually mean you shouldn't take sibutramine. They include heart disease, high blood pressure, irregular heartbeat, history of stroke, an eating disorder, depression or other mood disorder. There are also many other medications that may cause adverse reactions if you take them with sibutramine. Be sure to tell your provider about all the medicines and supplements you take.
Some of the most common side effects are headache, dry mouth, constipation, nervousness, trouble sleeping, runny nose and back pain. More serious side effects include increased blood pressure, fast or pounding heartbeat, chest pain, shortness of breath, dizziness and confusion. Contact your provider immediately if you have any of these symptoms.
How well do these medications work?
Unless you eat a low-calorie diet and exercise at the same time as you take them, they may not work at all. But if you do all three, you may lose from 5-10% of your current body weight within one year. So if you weigh 170, you might lose up to 17 pounds. That may not seem like much if you're very overweight. But it is enough to lower blood sugar and blood pressure in many people. That's a significant health benefit.
How long would I have to take one of these drugs?
That's a major issue. Most people regain any weight they lose. So you might have to keep taking it to keep off the weight you lose. Even then, you may not keep it off unless you continue to eat less and be active. And these drugs haven't been tested for long-term side effects.
Why is it so tough to develop a more effective weight loss medication?
Extra pounds had survival value as humans evolved. Getting enough to eat was job #1 for us until very recently. Storing calories as fat was insurance. Extra weight got us through days when we couldn't find food, and through longer periods of famine. It may have helped us to fight off infections and survive diseases. Even today, when famine and infectious disease are less threatening, overweight Americans tend to live longer than normal, underweight or obese people do.
So our bodies developed multiple methods to store fat and regain any we lose. Genes determine some, so they vary among us. They include mechanisms to:
- make us crave high-calorie, sweet and fatty foods
- extract every calorie out of what we eat
- slow metabolism when we eat less to conserve energy
- increase hunger when we lose weight
- stimulate hunger when our blood sugar goes down, no matter how overweight we may be
To be highly effective, a weight-loss drug may have to affect at least 3 complex systems: your hormones, brain and gut. If it only treats one (the brain in the case of sibutramine, the gut with orlistat) its effect may be limited. The body may find another way to compensate and hold onto fat. That's why many of the new drugs under development are combination drugs.
What to do? It's tough to lose weight, so the best approach is to avoid gaining any. Even if you're overweight or obese, do your best not to gain any more. If you want to lose weight, do it slowly so that your body doesn't trip you up. We have many tips on both in this week's Cover Story If Weight-Loss Diets Don't Work, What Does?
Developed on 11/05/09 by J. Johnson (BA English composition, Northwestern University). Published on 11/16/09.
References:
- Orlistat, Relay Health Medication Advisor, 2009.
- Sibutramine, Relay Health Medication Advisor, 2009.
- Sibutramine at http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601110.html
- Orlistat at http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601244.html
- Medicine's Elusive Goal: A Safe Weight-Loss Drug at http://www.nytimes.com/2009/10/17/business/17obesity.html?ref=health
- FDA Issues Early Communication about Ongoing Safety Review of Weight Loss Drug Orlistat-Review includes both prescription drug Xenical and OTC drug Alli at http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm180057.htm
- New Weight-Loss Drug Shows Promise in Early Study at http://www.nlm.nih.gov/medlineplus/news/fullstory_59833.html
- Medications for Weight Reduction George A. Bray, MD Endocrinology and Metabolism Clinics - Volume 37, Issue 4 (December 2008)
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