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Prescription weight-loss drugs

By Mayo Clinic Staff

Are you an adult whose weight causes serious health conditions? Have you tried to diet and exercise but haven’t been able to lose enough weight? If your answer to these questions is yes, a prescription weight-loss drug may be for you.

Prescription drugs are medicines that a healthcare professional prescribes. You can’t buy them off the shelf in a drugstore like a common pain reliever.

Weight-loss drugs are meant to be only part of a weight-loss plan. Healthy eating, behavior changes and exercise are vital for prescription weight-loss drugs to work well.

Your healthcare professional may suggest a weight-loss medicine for you if you haven’t been able to lose weight through diet and exercise and your:

Before choosing a medicine for you, your healthcare professional asks about your health history and health challenges. Then your healthcare professional talks with you about the pros and cons of prescription weight-loss drugs.

These medicines aren’t for everyone. For example, you shouldn’t take prescription weight-loss drugs if you’re pregnant or breastfeeding or trying to get pregnant.

Prescription weight-loss drugs that you can use for more than 12 weeks lead to major weight loss compared with treatment that has no active medicine, called a placebo. Weight-loss medicine and lifestyle changes lead to greater weight loss than lifestyle changes alone.

Taking these medicines for a year can mean a loss of total body weight of 3% to 18% more than that lost with lifestyle changes alone. That may not seem like a lot. But losing 5% to 10% of your weight and keeping it off can help you. That amount of weight loss can lower blood pressure, blood sugar levels and levels of fats in the blood called triglycerides.

Mild side effects are common. They include having an upset stomach, trouble passing stool and loose stools. These side effects may get better over time. Rarely, serious side effects can happen.

Ask your healthcare professional about all treatment choices. And ask about what each medicine can do for you and what the risks are.

Weight-loss drugs can be costly. Insurance doesn’t always pay for them. Ask your insurance company about your coverage.

Many people gain back some of the weight they lost when they stop taking weight-loss drugs. But practicing healthy lifestyle habits may help limit weight gain.

How long you take a weight-loss drug depends on how well the medicine works for you. If you lose enough weight to improve your health and don’t have serious side effects, your healthcare professional may suggest that you take the medicine long term.

If you haven’t lost at least 5% of your body weight after taking the full dose of a medicine for 3 to 6 months, your healthcare professional may suggest another treatment, such as another weight-loss drug.

The U.S. Food and Drug Administration, also called the FDA, has approved six prescription weight-loss drugs for long-term use:

Most prescription weight-loss drugs work by making you feel less hungry or full longer. Some do both. Orlistat causes your body to take in less fat from food.

Bupropion-naltrexone is a mix of two medicines. Naltrexone treats alcohol and opioid overuse. Bupropion treats depression and helps people stop smoking. When combined into one pill, this medicine helps people lose weight. You take it by mouth once or twice a day.

Bupropion-naltrexone can raise blood pressure. So your healthcare professional needs to check your blood pressure regularly at the start of treatment. Common side effects include upset stomach, headache and trouble passing stool. The medicine also may cause depression, changes in thinking and suicidal thoughts.

Liraglutide is a daily shot. In a lower dose, it treats diabetes. Upset stomach and vomiting are common complaints.

You take prescription orlistat by mouth three times a day. You also can get the pill in a lower strength without a prescription (Alli). Orlistat can cause side effects such as passing gas and having loose stools. You follow a low-fat diet when taking this medicine.

Rarely, people who take orlistat have serious liver injury. But research hasn’t shown that the medicine causes liver injuries.

Phentermine-topiramate is a mix of the weight-loss drug phentermine and the anticonvulsant topiramate. You take it by mouth once a day.

Phentermine is a Schedule IV drug. This is a label given to drugs that have a risk of misuse. But the rate of misuse seems to be low.

Side effects may include a faster heart rate and higher blood pressure, not being able to sleep, trouble passing stool, and being nervous. Topiramate raises the risk of birth defects.

Phentermine by itself (Adipex-P, Lomaira) is another weight-loss medicine. It’s one of four weight-loss drugs the FDA approved for use for short-term use. Short-term use is less than 12 months.

This medicine is given as a weekly shot. This type of medicine under other brand names and dosages also treats diabetes. The brand names for diabetes treatment are Ozempic, a shot, and Rybelsus, a pill you take by mouth.

Side effects may include upset stomach and vomiting, loose stools, and belly pain.

This medicine is given as a weekly shot. Under the name Mounjaro, it treats diabetes.

Side effects can include upset stomach, vomiting, loose stools, belly pain and trouble passing stool.

The FDA also has approved setmelanotide (Imcivree). But it’s only for people age 6 and older who have obesity due to one of these rare conditions that are passed through families, called inherited:

Setmelanotide doesn’t treat any of the gene issues that cause these conditions. But taken as a daily shot, it can help people with one of these conditions lose weight. It can make them want to eat less and make them feel full sooner. And it may help them burn more calories.

Side effects include headache, skin darkening, upset stomach, loose stools, belly pain, depression and thoughts of suicide.

The Food and Drug Administration has concerns about people getting and using weight-loss drugs from compounding pharmacies. These pharmacies make versions of medicines, such as semaglutide and tirzepatide. The FDA doesn’t test these medicines for how well they work or how safe they are.

The FDA urges people to get a prescription from their healthcare professionals and have the prescription filled at a state-licensed pharmacy.

Weight-loss drugs aren’t an easy answer to weight loss. But they may help you make the lifestyle changes that you need to lose weight and improve your health.

© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.
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Prescription weight-loss drugs

Are you an adult who has serious health problems because of your weight? Have you tried diet and exercise but haven’t been able to lose enough weight? If you answered yes to these questions, a prescription weight-loss drug may be a choice for you.

Prescription drugs are medicines that a health care provider prescribes for you. You can’t buy them off the shelf in a drug store like you can buy nonprescription medicines.

Just know that you need to use prescription weight-loss drugs in addition to — not instead of — a healthy diet and exercise.

Your health care provider may suggest a weight-loss drug for you in some cases. These include if you haven’t been able to lose weight through diet and exercise and your:

Before choosing a medicine for you, your health care provider thinks about your history and health challenges. Then your provider talks with you about the pros and cons of prescription weight-loss drugs.

These drugs aren’t for everyone. For example, you shouldn’t take prescription weight-loss drugs if you’re trying to get pregnant, are pregnant or are breastfeeding.

Prescription weight-loss drugs that you can use for more than 12 weeks, called long-term use, lead to major weight loss compared with an inactive treatment that doesn’t use medicine, called a placebo. The combination of weight-loss medicine and lifestyle changes leads to greater weight loss than do lifestyle changes alone.

Taking these drugs for a year can mean a loss of total body weight of 3% to 12% more than that lost with lifestyle changes alone. That may not seem like a lot. But losing 5% to 10% of your total weight and keeping it off can have important health benefits. For example, it can lower blood pressure, blood sugar levels and levels of fats in the blood called triglycerides.

Mild side effects, such as nausea, constipation and diarrhea, are common. They may lessen over time. Rarely, serious side effects can happen. That’s why it’s important to ask your health care provider about all treatment choices. And ask about the possible benefits and risks of each drug.

Weight-loss drugs can be expensive and aren’t always paid for by insurance. Ask your insurance company about your coverage.

Many people gain back some of the weight they lost when they stop taking weight-loss drugs. But practicing healthy lifestyle habits may help limit weight gain.

How long you take a weight-loss drug depends on whether the drug helps you lose weight. If you’ve lost enough weight to improve your health and you haven’t had serious side effects, your health care provider may suggest that you take the drug long term.

If you haven’t lost at least 5% of your body weight after taking the full dose of a drug for 3 to 6 months, your health care provider will probably change your treatment. They may switch you to a different weight-loss drug.

Six weight-loss drugs have been approved by the U.S. Food and Drug Administration (FDA) for long-term use:

Most prescription weight-loss drugs work by making you feel less hungry or fuller. Some do both. The exception is orlistat. It affects the way your body absorbs fat.

Bupropion-naltrexone

Bupropion-naltrexone is a combination drug. Naltrexone is used to treat alcohol and opioid addiction. Bupropion is a drug to treat depression, called an antidepressant, and a drug to help people stop smoking, called a quit-smoking aid. Like all antidepressants, bupropion carries a warning about suicide risk. Bupropion-naltrexone can raise blood pressure. So your provider will need to check your blood pressure regularly at the start of treatment. Common side effects include nausea, headache and constipation.

Liraglutide

Liraglutide also is used to manage diabetes. It’s given as a daily shot. Nausea is a common complaint. Vomiting may limit its use.

Orlistat

You also can get orlistat in a reduced-strength form without a prescription (Alli). Orlistat can cause side effects such as passing gas and having loose stools. You need to follow a low-fat diet when taking this medicine. In rare cases, people have had serious liver injury with orlistat. But researchers haven’t found that the drug causes liver injuries.

Phentermine-topiramate

Phentermine-topiramate is a combination of a weight-loss drug called phentermine and an anticonvulsant called topiramate. Phentermine has the potential to be misused because it acts like a stimulant drug called an amphetamine. Other possible side effects include an increase in heart rate and blood pressure, insomnia, constipation, and nervousness. Topiramate increases the risk of birth defects.

Phentermine by itself (Adipex-P, Lomaira) also is used for weight loss. It’s one of four similar weight-loss drugs approved for use for less than 12 weeks, called short-term use. The other drugs in this group aren’t often prescribed.

Semaglutide

Semaglutide also is used to help control type 2 diabetes. You take it as a weekly shot to manage obesity.

It can cause side effects such as:

Setmelanotide

The FDA has approved setmelanotide only for people age 6 and older who have obesity due to one of these rare inherited conditions:

To take the drug, you’ll need to have test results that show you have one of these conditions. Setmelanotide doesn’t treat any of the gene problems that cause these conditions. But it can help you lose weight. It can lessen your appetite and make you feel fuller. And it may help you burn calories while your body is at rest.

You take setmelanotide as a daily shot. It can cause side effects such as:

Never give setmelanotide to a child under 6 years old. It can cause newborns and babies to have dangerous reactions.

Weight-loss drugs aren’t an easy answer to weight loss. But they may help you make the lifestyle changes that you need to practice to lose weight and improve your health.

© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.

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