Doctors sometimes prescribe weight loss medications. These prescription medications often are used in addition to lifestyle modifications—reduced-calorie diet, increased physical activity—for chronic weight management in people at risk for weight-related complications.

Weight loss medications include sibutramine (Meridia) and orlistat (Xenical). In February 2007, the Food and Drug Administration (FDA) approved a reduced-strength version of orlistat (alliā„¢) for over-the-counter use in people over the age of 18.

Sibutramine (Meridia) alters brain chemistry so that the patient does not feel the urge to overeat. However, this medication has not been proven to be more effective than changes in diet and exercise. Side effects include insomnia, headache, constipation, dry mouth, and increased blood pressure. In October 2010, Meridia was voluntarily withdrawn from the market in the United States because of clinical trial data showing that the drug may increase the risk for adverse cardiovascular events (e.g., heart attack, stroke).

Orlistat (Xenical) causes the intestines to absorb less fat. This medication can affect the way the body absorbs nutrients, so doctors often recommend that patients take a multivitamin as well. The main side effect, an increased number of bowel movements (which can be oily), can be managed by decreasing fat intake.

The safety and effectiveness of many over-the-counter remedies are often disputed. These products include St. John's Wort, herbal laxatives, chitosan, and garcinia. Patients are advised to research these remedies carefully and consult with a physician before taking them.

In many cases, the products are labeled "natural" or "herbal," but they often are not scientifically tested for safety or effectiveness and they can interfere with other medications or conditions.

In December 2014, the FDA approved liraglutide injection (Saxenda) for use in adults with a body mass index of 30 or higher or a BMI of 27 or greater who have at least one complication like high blood pressure, type 2 diabetes, high cholesterol. This medication is a glucagon-like peptide-1 receptor agonist and should not be used with other drugs in this class, including Victoza (a type 2 diabetes medication). It may cause serious side effects such as pancreatitis, gallbladder disease, impaired kidney function, and suicidal thoughts. Common side effects include nausea and vomiting, diarrhea, constipation, and low blood sugar.

Updated by Remedy Health Media

Publication Review By: Karen Larson, M.D.

Published: 15 Nov 2006

Last Modified: 30 Jul 2015