Weight-Loss Medicines

About This Medicine

Make sure you know about each of the medicines you take. This includes why you take it, how to take it, what you can expect while you're taking it, and any warnings about the medicine.

The information provided here is general. So be sure to read the information that came with your medicine. If you have any questions or concerns, talk to your pharmacist or doctor.

What are some examples?

Here are some examples of weight-loss medicines. For each item in the list, the generic name is first, followed by any brand names.

• Bupropion/naltrexone (Contrave): This medicine may reduce your appetite. It may help you avoid overeating.
• Liraglutide (Saxenda): You take this medicine as a shot once a day. It may help you eat less.
• Orlistat (Xenical). Orlistat 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. It's 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): This medicine combines the drugs phentermine and topiramate. Taking it once a day can help you eat less.

Why are prescription weight-loss medicines used?

Doctors prescribe weight loss medicines for people who are obese or overweight and have other health problems, such as high blood pressure or diabetes. These medicines may help some people who haven't been able to lose weight with diet and exercise.

How well do they work?

Different medicines produce different results in different people.

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.
• Orlistat (Xenical), some lost 6 to 7 pounds.
• Phentermine/topiramate (Qsymia), some lost 9 to 24 pounds.

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.

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.

What about side effects?

Most weight-loss medicines have side effects like nausea, vomiting, headaches, and constipation. Some medicines are more likely to cause side effects than others. For example, nausea is a common side effect of Contrave and Saxenda. Xenical can cause changes in bowel habits. These changes may include 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 2}

If your doctor prescribes a weight-loss medicine for you, tell them 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. The doctor will watch to see if your weight loss improves your type 2 diabetes, cholesterol, and blood pressure.

General information about side effects

All medicines can cause side effects. Many people don't have side effects. And minor side effects sometimes go away after a while.

But sometimes side effects can be a problem or can be serious.

If you're having problems with side effects, talk to your doctor. Your doctor may be able to lower your dose or change to a different medicine.

Always be sure you get specific information on the medicine you're taking. For a full list of side effects, check the information that came with the medicine you're using. If you have questions, talk to your pharmacist or doctor.

What are some cautions about prescription weight-loss medicines?

Using weight-loss medicines can put you at risk for increased blood pressure, a faster heart rate, headaches, sleep problems, and unpleasant changes in bowel habits. It is possible to misuse some of these medicines. Weight-loss medicines also can harm unborn babies. Women who are pregnant should not take these medicines.

General cautions for all medicines

Allergic reactions.

All medicines can cause a reaction. This can sometimes be an emergency. Before you take any new medicine, tell the doctor or pharmacist about any past allergic reactions you've had.

Drug interactions.

Sometimes one medicine may keep another medicine from working well. Or you may get a side effect you didn't expect. Medicines may also interact with certain foods or drinks, like grapefruit juice and alcohol. Some interactions can be dangerous.

Harm during pregnancy or breastfeeding.

If you are pregnant, trying to get pregnant, or breastfeeding, ask your doctor or pharmacist if all the medicines you take are safe.

Other health problems.

Before taking a medicine, be sure your doctor or pharmacist knows about all your health problems. The medicine for one health problem may affect another health problem.

Always tell your doctor or pharmacist about all the medicines you take. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. That information will help prevent serious problems.

Always be sure you get specific information on the medicine you're taking. For a full list of warnings, check the information that came with the medicine you're using. If you have questions, talk to your pharmacist or doctor.

What should you know about 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.