The Food and Drug Administration (FDA) has approved four drugs in recent years that are designed to help obese adults shed some of their excess weight, but consumers' actual knowledge about the drugs varies greatly. Although weight-loss results are modest, these drugs — Belviq (lorcaserin hydrochloride), Contrave (naltrexone hydrochloride and bupropion hydrochloride), Qsymia (phentermine and topiramate), and Saxenda (liraglutide)  — “can give some patients an edge when it comes to losing weight, but they come with risks,” says Kim Gudzune, MD, MPH, assistant professor of medicine and an obesity expert at Johns Hopkins Medicine in Baltimore.
So despite the drugs' effectiveness in jump-starting weight loss, some physicians are still reluctant to recommend them given the uncertainties about their risks and side effects. Before you see your doctor, here are 10 important things you need to know about prescription weight-loss medications:
  1. Weight-loss medications are approved for people with significant weight problems. Weight-loss drugs aren’t meant for those who want to lose a few pounds before the class reunion or a beach vacation. According to the FDA, you need to have a significant weight problem to be prescribed a weight-loss drug, such as a body mass index of more than 30, or weight that makes it difficult for you to control other health issues, like high blood pressure, high cholesterol, or type 2 diabetes.
  2. Many of these drugs are off-limits to pregnant women or those trying to get pregnant. If taken during pregnancy, Belviq, Contrave, and Qsymia can cause harm to a fetus. Women of childbearing age should use contraception consistently while taking these drugs, and should be tested before they start taking any of them to make sure they aren’t pregnant.
  3. The results may be modest — but the health benefits can be significant. According to the FDA, people taking Qsymia can, on average, expect to lose 5 percent of their weight, or 5 pounds for every 100. Those taking Saxenda had an average loss of 4 to 5 percent of total body weight in trials. While that may not seem like much, losing 5 percent of your body weight is an excellent short-term goal. Experts at the Centers for Disease Control and Prevention (CDC) advise that losing even 5 or 10 percent of your body weight can produce positive health benefits, including lower blood pressure, better blood sugar control, and improved blood cholesterol. According to the Obesity Action Coalition, a 5 to 10 percent loss can result in a 5 point increase in HDL (good cholesterol) and a 40 milligram (mg) decrease in triglycerides — harmful fat-like particles in the blood. A 5 to 10 percent drop in your weight can also decrease both systolic and diastolic blood pressure by 5 mmHg, on average. Talk to your doctor about a dietary plan or calorie goal that will help you reach a healthy weight.
  4. A companion diet and exercise plan is needed to meet long-term goals. “Weight-loss drugs are to be used as a supplement, not a substitute, for your weight-loss efforts,” says Nikhil V. Dhurandhar, PhD, president of The Obesity Society, and a professor and chair of the department of nutritional sciences at Texas Tech University in Lubbock. You still need to exercise and eat a reduced-calorie diet if your goal is to lose significant weight. For extra support and calorie-controlled meal ideas, try Everyday Health's free Meal Planner, which can be personalized to meet your weight-loss goals.
  5. These drugs come with side effects. That’s true of every drug for any disease, Dr. Dhurandhar says. Qsymia can increase heart rate in some people, according to the FDA, and Contrave can cause seizures. In addition, side effects can make it hard to stick with your prescribed course, Dr. Gudzune notes.
  6. Your doctor may need to change your dose over time. “Not everyone responds to the same drug in the same fashion, whether it’s weight-loss drugs or other drugs,” Dhurandhar says. Like any new medication, your physician may put you on a smaller dose to see how well the medication is tolerated. Be patient: Doctors have a small number of weight-loss drugs to choose from, and it can take time for them to come up with the right combination for you, he says. Keep a journal with information about how you're feeling, changes in weight, and what you've been eating to share with your doctor for optimal results.
  7. You may have to be on the drugs long-term. “Taking a medication for three months usually doesn’t do the trick, and you gain the weight back when you stop,” Gudzune says. Like any weight-loss effort, you need to commit to a long-term plan to lose weight and keep it off.
  8. All weight-loss medications aren’t created the same: Some block fats, while others curb appetite. The ones that block fat in the food you eat can have unpleasant gastrointestinal side effects. Orlistat, an oral medication that blocks fat absorption, is sold over-the-counter as Alli, and as the prescription Xenical. Other oral medications, like Belviq, Contrave, and Qsymia act as appetite suppressants. Saxenda is an injectable medication that mimics a hormone that tells your brain when you’re full. Talk to your doctor about a prescription and a plan that works with your lifestyle.
  9. Only about a third of insurance companies cover weight-loss drugs. And another third have restrictions on what they will approve and when, according to Kaiser Health News. Visit your insurer's Web site to review a list of prescriptions that your plan covers. If your plan doesn’t cover these medications, you may qualify for a discount to help defray the cost of medication. The drugs can cost a couple of hundred dollars a month out-of-pocket, Gudzune says, so it’s worth doing your homework.
  10. Some doctors are reluctant to address weight-loss drugs, and you may need to make a case for a prescription. In 2013, the American Medical Association recognized obesity as a disease, yet not all doctors treat it as such. Some doctors are reluctant to prescribe weight-loss drugs because they figure, "why expose people to the risks of drugs for something that’s not a disease?" Dhurandhar says. Doctors may also be reluctant because some drugs have been pulled from the market over the years due to extreme side effects and risks, Gudzune says. 
Remember that losing as little as 5 percent of your body weight can have significant health benefits, including reducing your risk of cancer and improving your cholesterol and blood pressure. If you're overweight or obese, don't be afraid to open up a dialogue with your physician about what kind of weight-loss help is available to you, including weight-loss plans, prescription drugs, nutritional counseling, and bariatric surgery.