The U. S. Food and Drug Administration (FDA) has approved six prescription drugs for weight loss. Five of these drugs – orlistat (Xenical, Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda) and semaglutide (Wegovy) – are approved for long-term use.
The sixth drug, setmelanotide (IMCIVREE), is only available to people who have been diagnosed with one of three specific rare genetic disorders, which must be confirmed by genetic testing. Eating less and exercising more are the foundations of successful weight loss that lasts. For some people, prescription weight-loss medications may be beneficial. Doctors usually prescribe them if your body mass index (BMI) is 30 or higher, or if it is at least 27 and you have a condition that may be related to your weight, such as type 2 diabetes or high blood pressure.
Orlistat is the only drug of its kind that is approved in the U. S. All other prescription weight-loss medications work by reducing appetite, including the following: phentermine, topiramate, liraglutide and semaglutide. If you use insulin for diabetes, tell your doctor before taking phentermine, as you may need to adjust your insulin dose.
You should not take phentermine if you have a history of heart disease, stroke, congestive heart failure, or uncontrolled high blood pressure. You should also not take it if you have glaucoma, hyperthyroidism, or a history of drug abuse, or if you are pregnant or breastfeeding. Qsymia has much lower amounts of phentermine and topiramate than when these drugs are given alone. Phentermine is the most commonly prescribed weight loss medication in the United States.
It helps suppress appetite and makes you feel fuller for longer. Phentermine is an amphetamine-like stimulant drug that can affect the heart. As such, it is usually used short-term (usually 12 weeks in a row). In a study that looked at nearly 800 people with a BMI greater than 25, 45.6% of people were able to lose 5% or more of their initial body weight after 12 weeks of phentermine use.
Qsymia combines a low-dose phentermine with topiramate, a drug used to treat seizures and migraines. Qsymia comes in a variety of doses. Research shows that Qsymia can help people lose weight, even at low doses (although Saxenda has a black warning box – the FDA's strongest alert to consumers and healthcare providers about very serious side effects – because animal studies have linked liraglutide and medicines like this one with certain thyroid tumors and thyroid cancer). It is important that you do not use Saxenda if you have had these conditions or have a family history of them.
Saxenda is not suitable for pregnant or breastfeeding women. Talk to your healthcare provider if you are taking medications that act as GLP-1 receptor agonists. Because Saxenda can delay stomach emptying, it is also important to ask your doctor how this may affect other prescription and over-the-counter medications you may be taking. Contrave combines naltrexone (used to treat substance abuse) and bupropion (an antidepressant marketed under the trade name Wellbutrin).
It is believed to work in the brain to regulate appetite and cravings. Like many weight-loss medications, your dose of Contrave will start low and you will take three capsules of Plenity with 16 ounces of water before lunch and dinner. The particles absorb water and mix with food from the stomach, helping you feel fuller and eat less. One study showed that 59% of people taking Plenity lost 5% or more of their body weight and 27% lost more than 10% of their weight.
This compares to 42% and 15%, respectively, in the placebo group. Orlistat is a lipase inhibitor, meaning it blocks the enzyme that helps absorb some of the fats from the foods you eat; that is, a smaller amount of fat you consume is converted into fat cells to become stubborn belly fat. Orlistat comes in two different strengths: an OTC 60 mg strength marketed as Alli and a prescription-only strength (120 mg) marketed as Xenical. Xenical is not as effective as other recipes for weight loss; a study comparing orlistat with liraglutide found that those who used it could lose more than twice as much weight as those taking orlistat. Wegovy is the new weight loss drug approved by the FDA and works in the same way as Saxenda, mimicking the action of GLP-1 hormone to suppress hunger. The dose is increased over the course of several weeks to months until a dose of 2.4 mg is reached.
In one study, the mean change in body weight was -14.9% in the Wegovy group versus -2.4% in the placebo group; 84 percent of people in the Wegovy group lost 5% or more of their body weight compared to 31.5% of those taking a placebo. Like Saxenda, Wegovy carries a black box warning because of the possibility that it may increase the risk of certain tumors and thyroid cancer; pancreatitis, gallbladder disease, kidney injury, low blood sugar and other conditions have also been reported with its use. Possible side effects of these short-term weight loss pills include increased heart rate, high blood pressure, trouble sleeping (insomnia), dry mouth, constipation and nervousness. Now people who are trying to lose weight have a new option: a drug called Wegovy (semaglutide) which is injected under the skin once a week. On average after one year of use people who take prescription weight-loss drugs lose 3% to 12% more body weight than those who just diet and exercise alone. If you have problems with your weight then a healthy eating plan combined with regular physical activity can help you lose weight and keep it off in the long term. Many weight-loss drugs had to be recalled due to heart valve disease, pulmonary hypertension and other serious problems.