Drugs for obesity lead to small weight losses
Publication Date:16/11/2007
Introduction
People who take a drug treatment for obesity lose just a small amount of extra weight compared with people who rely on diet and exercise instead of pills, a big review of the research has found. Most people who take one of these drugs are still obese or very overweight one to four years later.
What do we know already?
Obesity is a serious problem that's affecting more and more people. Being obese increases a person's risk of several health problems, including diabetes, high blood pressure and heart disease. Losing weight can reduce this risk.
Doctors decide if someone's weight is healthy by measuring their body mass index, or BMI. You can calculate your BMI by dividing your weight in kilograms by your height in metres squared. A BMI of 25 or more is classed as overweight, and 30 or more is classed as obese.
If you're trying to lose weight, the first thing your doctor will advise you to do is to eat less and exercise more. You can also get advice from a professional to help you change your diet and exercise habits. Drug treatments are reserved for people who are classed as obese (they have a BMI over 30) and who have already lost some weight (at least 2.5 kilograms or 5.5 pounds).
The researchers in the present study wanted to find out what happened to people who took an anti-obesity drug for more than a year, including what side effects they got.
What does the new study say?
People who took an anti-obesity drug for between one and four years lost more weight than people who didn't have drug treatment, but on average the extra loss was less than 5 kilograms (11 pounds). That may sound like a reasonable amount, but in the study it meant that people lost less than 5 percent of their body weight.
People who took the drugs also had some improvements in health, such as lower cholesterol, lower blood pressure and a reduced risk of diabetes. But all the drugs have side effects, some of them serious.
Tell me more about the study's findings
Researchers in this study looked at three drugs used to treat obesity: orlistat (Xenical), sibutramine (Reductil) and rimonabant (Acomplia). They looked at what happened to people who took one of these drugs for at least a year, compared to those who didn't take an anti-obesity pill. People in most of the studies were also given advice about diet and exercise. Their average weight before treatment was 100 kilograms (15.7 stone).
The researchers found that on average, taking orlistat led to 2.9 kilograms extra weight loss, sibutramine 4.2 kilograms and rimonabant 4.7 kilograms.
People's health improved in several ways. For example, all three drugs reduced people's cholesterol levels. People who took orlistat saw a fall in their blood pressure and were less likely to get diabetes. Rimonabant also reduced people's blood pressure. But not all the changes were good. Sibutramine increased people's blood pressure and caused a fast heartbeat.
Side effects were common with all the treatments and caused many people (between 30 and 40 percent) to leave the studies. People who took orlistat had oily stools, an oily leakage from their bowels and an urgent need to empty their bowels. Those taking sibutramine had insomnia, nausea, a dry mouth and constipation. And people who took rimonabant were at increased risk of getting depressed, anxious, irritable and aggressive.
Where does the study come from?
The study was done by researchers from the universities of Alberta and Calgary in Canada and from the Department of Nutrition in Brazil. It was published in a journal called the BMJ (British Medical Journal).
How reliable are the findings?
The review included the results from 30 good-quality studies of obesity drugs. However, the fact that so many people didn't stick with the treatment makes findings from individual studies less reliable.
What does this mean for me?
These findings are important if you are obese and are finding it difficult to lose weight. They show that taking an anti-obesity pill may help you lose more weight than you might have done without the treatment, but that the extra weight loss is likely to be quite small. The likelihood that you will get side effects from one of these pills is also quite high.
What should I do now?
If you're obese and want to lose weight, you may want to talk to you doctor about whether trying an anti-obesity pill is the right option for you. If you and your doctor decide that this might help you lose weight, it's important to remember that you also need to eat less and exercise more. People who change their lifestyle in this way as well as taking an anti-obesity pill lose the most weight. You can also ask a health professional to help you change your habits around eating and exercise.
If you're already taking an anti-obesity pill and are worried that it's not helping you, you should see your doctor. You may need to look at your lifestyle to see if you're doing the right things to maximise your chances of losing weight. If your medication is causing side effects, it's important not to stop taking it without seeing your doctor first.
From:
Rucker D, Padwal R, Li SK, et al. Long term pharmacology for obesity and overweight: updated meta-analysis. November 2007 (early online publication). Available at http://www.bmj.com (accessed on 14 November 2007).
To find out more about what treatments work best for people trying to lose weight, see our information on obesity.
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© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
