Obesity is a chronic condition that affects many people. If you are struggling with excess weight, you may find that a healthy eating plan and regular physical activity help you lose weight and maintain weight loss over the long term. But if these lifestyle changes are not enough, prescription medications for obesity treatment may be a helpful part of your weight-control program.
When combined with healthy eating and regular physical activity, prescription obesity drugs may help some people lose weight and improve their health. But these drugs have side effects and may not work for everyone.
This fact sheet will tell you more about the prescription medications that may be used to treat obesity. Talk to your health care provider if you think these medications may help you.
Who may use obesity medications?
Health care providers often use the body mass index (BMI) to help decide who may benefit from weight-loss drugs. BMI estimates overweight and obesity based on your height in relation to your weight. Your doctor may prescribe you a medication to treat your obesity if you are an adult with
- a BMI of 30 or greater, or
- a BMI of 27 or greater and you have obesity-related medical problems, such as high blood pressure, type 2 diabetes, or high cholesterol
To check your BMI, see the Resource section for a link to the Online BMI Calculator. Before using a weight-loss drug, you should first try to lose weight by changing your eating and physical activity habits.
How do these drugs work?
Prescription drugs for the treatment of obesity work in different ways. For example, some drugs may help you feel less hungry or feel full sooner. Others may make it hard for your body to absorb fat from the foods you eat.
These medicines are meant to help people who may be having health problems related to excess weight. See the box “Who may use obesity medications?” for more information. Your doctor will also consider the drugs’ side effects, your family’s medical history, and your current health issues and medicines.
What are the benefits?
When combined with changes to eating and physical activity, prescription drugs may help some people lose weight (usually less than 10 percent of their body weight). Results vary by drug and by person. Losing weight may help improve your health by lowering blood sugar, blood pressure, and triglycerides (other fats in the blood). Weight loss of 5 to 10 percent can also improve inflammation profiles and improve how patients feel and their mobility.
Most weight loss takes place in the first 6 months of starting the medicine. After that time, you may lose weight more slowly or begin to regain weight.
What are the concerns?
Because obesity drugs are used to treat a condition that affects millions of people, the chance that side effects may outweigh benefits is of great concern. This is why one should never take a weight loss medicine only for cosmetic benefit. In the past, some drugs for obesity treatment were linked to serious health problems. An example is sibutramine (sold as Meridia), recalled in 2010 because of concerns related to heart disease and stroke.
Possible side effects vary by drug and how it acts on your body. See the next section of this fact sheet for the specific side effects of each weight-loss drug. Most side effects are mild and usually improve if you continue to use the drug.
What drugs are available?
The Food and Drug Administration (FDA) is the Government agency that reviews and approves prescription drugs for treating specific health problems. Three drugs, orlistat, lorcaserin, and phenterminetopiramate, are approved for long-term use. This means that you may take them for several months at a time, even years.
Other weight-loss drugs that curb appetite are only approved by the FDA for short-term use (a few weeks), but some doctors prescribe them for longer periods. These medications are also controlled substances because of their potential for abuse. Most weight-loss drugs are only approved for use by adults. Orlistat is approved for children ages 12 and older. Weight loss medications should never be used during pregnancy, and weight loss is not advised during pregnancy. Women who are thinking about becoming pregnant should avoid some of these drugs, as they may harm an unborn baby.
When necessary, we will provide pharmaceutical support for our patients:
Orlistat (Xenical and Alli)
The drug orlistat, sold under the brand name Xenical (pronounced ZEN-i-cal), has been available since 1999. It is approved for use by adults and children ages 12 and older.
The over-the-counter version of orlistat is sold under the brand name Alli. The two drugs contain different amounts of orlistat. Xenical contains 120 mg, while Alli contains 60 mg. Alli is not approved for use by children.
Orlistat will stop about one-third of the fat from the food you eat from being digested. It does so by blocking the enzyme lipase, which breaks down fat. When fat is not broken down, the body cannot absorb it, so fewer calories are taken in. After 1 or 2 years of taking orlistat, patients may lose about 5 to 7 pounds.
Side effects: Common side effects of orlistat include stomach pain, gas, diarrhea, and leakage of oily stool. These side effects are generally mild and temporary, but may be worse when you eat high-fat foods. You should eat a low-fat diet (less than 30 percent of calories from fat) before starting to take this drug. Because orlistat prevents some vitamins from being absorbed, you should take a multivitamin while using orlistat.
Rare cases of severe liver injury have been reported. Stop using the drug and see your health care provider immediately if you develop symptoms of liver problems. These symptoms may include dark urine, itching, light-colored stools, loss of appetite, or yellow eyes or skin. Orlistat should not be taken with cyclosporine.
Belviq (pronounced BEL-VEEK), works by affecting chemicals in your brain that help decrease your appetite and make you feel full, so you eat less.
In studies done as part of the drug approval process, almost half (47 percent) of patients taking Belviq lost at least 5 percent of their initial body weight at 1 year. If you do not lose 5 percent of your weight within 12 weeks of being on the drug, it is unlikely that the medicine will work for you, and it should be stopped.
Side effects: Common side effects of Belviq include headaches, dizziness, feeling tired, nausea, dry mouth, cough, and constipation. A rare but serious side effect is serotonin syndrome (high fever, muscle rigidity, and confusion), which can occur if the drug is taken along with SSRI antidepressants or MAOI medications. Belviq, as with all weight-loss agents, should not be taken if you are pregnant or planning to become pregnant.
Phentermine works by stimulating the hypothalamus gland, the region of the brain that controls the autonomic nervous system, regulating sleep cycles, body temperature, appetite, etc. Phentermine should not be used as a substitute for proper diet or exercise. For maximum effects, it must be used in conjunction with a reduced-calorie diet and/or exercise. Any modifications in your diet, activity level, and behavior must be developed and continued long-term in order to continue losing weight and prevent the lost weight from returning.
Phentermine is usually prescribed for short periods of 3 months, as the effects of phentermine tend to wear off after some time, while side effects remain. To help you keep the weight off after using phentermine, Phen Caps weight loss supplement will help to maintain your eating habits and curb your appetite, while optimizing your energy.
Side effects: People who have used phentermine have reported palpitations, tachycardia, elevation of blood pressure, ischemic event; tremor, anxiety, restlessness, dizziness, insomnia, euphoria, dysphoria, and headache; dryness of the mouth, unpleasant taste, diarrhea, and constipation; urticaria; impotence and changes in libido.
Topiramate is a medicine approved to control seizures. Among more than 3,300 overweight or obese patients, those who took topiramate for at least four months lost 11.8 pounds more on average than individuals who took a placebo1.
Side effects: Common side effects include blurred vision, double vision, eye pain, or rapidly decreasing vision, burning prickling or tingling sensations, clumsiness or unsteadiness, confusion, uncontrolled back-and-forth or rolling eye movements, dizziness, drowsiness, eye redness, generalized slowing of mental and physical activity, increased eye pressure, memory problems, menstrual changes, menstrual pain, nervousness, speech or language problems, trouble in concentrating or paying attention, or unusual tiredness or weakness. Less common side effects include abdominal or stomach pain, fever, chills, sore throat, lessening of sensations or perception, mood or mental changes, or red irritated or bleeding gums. Rare side effects associated with topiramate include blood in the urine, decrease in sexual performance or desire, difficult painful or frequent urination, hearing loss, itching, loss of bladder control, lower back or side pain, nosebleeds, pale skin, red or irritated eyes, ringing or buzzing in the ears, skin rash, swelling, trouble breathing.
Other Appetite Suppressants
These drugs promote weight loss by increasing one or more brain chemicals that affect appetite. You may feel less hungry or feel full sooner when taking these drugs. They are FDA approved only for a short period of time (up to 12 weeks). Some doctors may prescribe them for longer periods of time.
Several appetite suppressants may be used to promote weight loss in adults. They include:
- phentermine (sold as Adipex-P, Oby-Cap, Suprenza, T-Diet, Zantryl)
- benzphetamine (sold as Didrex)
- diethylpropion (sold as Tenuate, Tenuate Dospan)
- phendimetrazine (sold as Adipost, Bontril PDM, Bontril Slow Release, Melfiat)
Among these types of drugs, phentermine is the one used most often in the United States.
Side effects: Common side effects of appetite suppressants include dry mouth, difficulty sleeping, dizziness, headache, feeling nervous, feeling restless, upset stomach, and diarrhea or constipation. Severe side effects may include chest pain, fainting, fast heartbeat, shortness of breath, confusion, and swelling in your ankles or feet. People with heart disease, high blood pressure, an overactive thyroid gland, or glaucoma should not use these drugs. These medications are controlled substances because of their potential for abuse.