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Weight-Loss Medicines

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.

Your doctors or Nurse Practitioner may prescribe these medicines for patients who are overweight, have obesity, or other health problems, such as high blood pressure or diabetes.

Non-prescription weight-loss products aren't recommended. Some have dangerous side effects, and 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.
  • 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.

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 and Saxenda. 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, and natural health products 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 4 to 5 kilograms (8 to 11 pounds).
  • Liraglutide (Saxenda), some lost 4 to 6 kilograms (8 to 13 pounds).
  • Orlistat (Xenical), some lost 3 to 3¼ kilograms (6 to 7 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, talk to your pharmacist about how much you will have to pay.

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.

References

Citations

  1. Diet, drugs, and surgery for weight loss (2015). Medical Letter on Drugs and Therapeutics, 57(1462): 21–28.

Credits

Adaptation Date: 8/18/2021

Adapted By: Alberta Health Services

Adaptation Reviewed By: Alberta Health Services

Adapted with permission from copyrighted materials from Healthwise, Incorporated (Healthwise). This information does not replace the advice of a doctor. Healthwise disclaims any warranty and is not responsible or liable for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.