Topic Overview

When are weight-loss medicines prescribed?

Losing weight can be hard work. Maybe you are wondering if taking medicines could help make it easier for you. Prescription weight-loss medicines may help some people who haven’t been able to lose weight with diet and exercise. But they don’t help everyone.

Doctors only prescribe these medicines for patients who are obese or overweight and have other health problems, such as high blood pressure or diabetes.

Some weight-loss products that you don’t need a prescription for are appetite suppressants and water-loss pills. But experts don’t recommend them. Some have uncomfortable or even dangerous side effects. Others have no proven benefit.

What are some examples of prescription weight-loss medicines?

• Bupropion/naltrexone (Contrave) may reduce your appetite. It may help you avoid overeating.
• Liraglutide (Saxenda) is given as a shot once a day. It may help you eat less.
• Lorcaserin (Belviq) is a medicine that you take twice a day. It can help you eat less and feel satisfied with eating smaller amounts of food.
• Orlistat (Xenical) prevents some of the fat calories you eat from being absorbed in your intestines. Prescription-strength orlistat is the only weight-loss medicine that is approved for children. It is meant to be used only in children over the age of 12. Orlistat is also available without a prescription under the brand name Alli. Alli is half as strong as Xenical. It should not be used by anyone under the age of 18.
• Phentermine/topiramate (Qsymia) combines the drugs phentermine and topiramate. Taking it once a day can help you eat less.

What are the side effects?

Most of the medicines have side effects like nausea, vomiting, headaches, and constipation. Some are more likely to cause side effects than others. For example, nausea is a common side effect of Contrave, Saxenda, and Belviq. Xenical can cause changes in bowel habits, including oily or fatty stool and being unable to control bowel movements. Sometimes the side effects are mild and go away over time.

Research shows that up to half of people who take weight-loss medicines quit because of side effects^{footnote 1}.

If your doctor prescribes a weight-loss medicine for you, tell him or her about all prescription and over-the-counter medicines, vitamins, herbs, and supplements that you take.

Your doctor will want to know about any side effects you have. He or she will watch to see if your weight loss improves your type 2 diabetes, cholesterol, and blood pressure.

How well do weight-loss medicines work?

Weight-loss medicines are used along with healthy eating and being more active. Without those lifestyle changes, you will gain the weight back if you stop taking the medicine. Many people regain the weight they lost after they quit taking the medicines.

Studies show that when people took:^{footnote 1}

• Bupropion/naltrexone (Contrave), some lost 8 to 11 pounds.
• Liraglutide (Saxenda), some lost 8 to 13 pounds.
• Lorcaserin (Belviq), some lost 4 to 8 pounds.
• Orlistat (Xenical), some lost 6 to 7 pounds.
• Phentermine/topiramate (Qsymia), some lost 9 to 24 pounds.

Medicine doesn’t work for everyone. If you don’t lose weight within 4 weeks after you start the medicine, it probably won’t help you.

How much do they cost?

Weight-loss medicines can range in cost. But they can be expensive. If you and your doctor have decided that you need a weight-loss medicine, make sure you know how much you will have to pay.

Take time to find out about how your insurance covers the cost of these medicines. Your insurance company may not pay for the medicines. Ask the customer service representative these questions:

• Are weight-loss medicines covered? For how long?
• Do I need to use a certain drugstore?
• What is my co-pay?

Many insurance companies also list this information on their websites.

What are the risks of using weight-loss medicines?

Weight-loss medicines can harm unborn babies. Women who are pregnant should not take these drugs. Women who do take them should use birth control to avoid getting pregnant.

If you decide to stop taking these medicines, talk to your doctor. Some weight-loss medicines should not be stopped suddenly.