Obesity is a known risk factor for developing type 2 diabetes (T2DM). The reasons for this are complex but include insulin resistance -- a problem with how the body responds to insulin, the hormone that normally helps metabolize blood sugar for energy. Weight loss has been established as the main way to reduce insulin resistance in people with both obesity and diabetes. Over the years, various medications in pill and injection form have been released that aim to help with weight loss and can benefit those with T2DM. While these interventions may help some individuals, a healthy lifestyle consisting of a balanced diet and regular exercise is the best long-term solution for losing weight with diabetes.
Diabetes Medications -- Pills
Certain medications prescribed for diabetes have the additional benefit of helping people lose weight. However, they have not been recommended for use as weight-loss medications alone. One example is metformin (Glucophage), the most common pill used to treat T2DM. Metformin is a member of the biguanide class of drugs, which act in multiple ways to lower blood sugar levels. It is not clear exactly how metformin causes weight loss, but a study in the April 2012 "Diabetes Care" showed that people with diabetes who took metformin for two years lost an average of 2 to 3 kg. Low blood sugar and gastrointestinal upset are possible side effects of metformin.
Diabetes Medications -- Injectables
Other diabetes drugs that aid weight loss are only available in injectable form. Exanatide (Byetta) and liraglutide (Victoza) are members of the drug class called incretin mimetics, also known as GLP-1 agonists. They treat T2DM by stimulating the pancreas to release insulin, thereby lowering blood sugar. They promote weight loss by decreasing appetite and slowing the passage of food from the stomach. A study published in the August 2010 "Pharmaceuticals" showed through various experiments that people with diabetes who took exanatide lost an average of 1 to 5 kg. Liraglutide was shown to result in weight loss of 5 to 6 kg when used at two different doses over a 56-week period; this study was published in the August 2015 "Journal of the American Medical Association." These drugs can have side effects like nausea, and kidney and thyroid problems, and treatment should be closely monitored.
A variety of pills can be prescribed to help with weight loss, apart from diabetes, and each works differently in the body. Multiple studies done on such medications were reviewed in the January 2014 "Journal of the American Medical Association:"
- Phentermine (Suprenza), an appetite suppressant, is the most widely prescribed medication for weight loss. The FDA has only approved its use for the short term (less than 12 weeks), but it is frequently prescribed off-label for longer. Several studies lasting between two and 24 weeks found that people taking phentermine lost an average of 3.6 kg more than those taking an inactive pill, or placebo. Some of the unwanted side effects from its use are changes in heart rate and blood pressure.
- Orlistat (Xenical) blocks lipase, an enzyme that breaks down and helps absorb fat in the intestines, thus leading to the excretion of fat when taken with or up to an hour after meals. A study found that people who took Orlistat while on a lower fat diet -- one with no more than 30 percent of calories from fat -- for 12 months lost an average of 3.6 kg more than those taking a placebo. Orlistat has been shown to cause diarrhea.
- Lorcaserin (Belviq) acts on chemical receptors in the brain to make a person feel full. People who took lorcaserin, in addition to improving nutrition and exercise, lost 3.2 kg more than those taking a placebo. Lorcaserin has also been shown to decrease body weight specifically in people with diabetes, but has a side effect of abnormally low blood sugar in T2DM, in addition to headaches and nausea.
- Phentermine/Topiramate-ER (Qsymia) is a combination drug, which adds to phentermine the anti-seizure drug topiramate, with a side effect of weight loss. A study published in the September 2013 "Expert Opinion on Drug Safety" showed that people with T2DM treated with the combination drug for 56 weeks saw an average of 6 percent more weight loss than those taking a placebo.
Warnings and Considerations
Speak to your healthcare provider to determine if any of the above medications for weight loss with T2DM are suitable for you. The use of medication for weight loss can come with many unwanted side effects and may interfere with other medications, both prescription and over-the-counter. For these reasons it's important to talk to your provider before starting or changing any medication to lose weight.
Medication alone is often not enough. The American Diabetes Association recommends lifestyle intervention through a balanced diet and regular exercise as the mainstay of healthy weight loss with T2DM.
If you experience severe symptoms of abnormally high blood sugar, such as blurry vision, increased thirst or hunger, increased urination, frequent infections, tingling in the hands or feet, changes in breathing or confusion; or symptoms of abnormally low blood sugar such as severe nausea, excess sweating or dizziness, seek medical care immediately.