by Rosalyn Carson-DeWitt, MD
Obesity has ballooned into a major public health problem in the United States. About 31% of American men and 35% of American women are obese, totaling about 97 million American adults. The public health costs of this include increased medical expenses, loss of productivity in the workplace, disability claims, and job discrimination. Treatment of obesity and diseases associated with obesity (such as high blood pressure, diabetes, arthritis, heart disease, and some cancers) accounts for 5-7% of total healthcare costs annually.
The battle against obesity is waged by frustrated individuals and by researchers who are working to understand the causes of obesity and to discover potential cures for this serious condition. Researchers have discovered that certain anti-seizure medications such as topiramate (ie Topamax) and zonisamide (ie Zonegran), an antidepressant bupropion (ie Wellbutrin, Zyban), and an experimental drug (ie rimonabant) may help obese patients lose weight.
Researchers believe that some obese people may overeat because they experience uncontrolled electrical impulses in the areas of the brain involved with pleasure sensations. When this happens, it may cause uncontrollable cravings for things such as food, alcohol, or nicotine.
People with epilepsy also have uncontrolled electrical impulses in the nerve cells of their brains. Anti-seizure medications like topiramate and zonisamide interfere with these uncontrolled electrical impulses, calming the electrical impulses and preventing seizures. Doctors who treat epilepsy noticed that patients taking topiramate and zonisamide tended to lose a significant amount of weight (an average of 11% of initial body weight). Researchers have noted that obese patients given zonisamide seemed to feel full sooner and have a decreased craving for sweets. Because of this effect, some researchers believe that these drugs may also dampen the activity of nerve cells in the pleasure centers of the brain, thereby relieving food cravings. How Could Wellbutrin Treat Obesity? The antidepressant bupropion (Wellbutrin; Zyban) is sometimes used to help people quit smoking. Researchers believe that, just as bupropion may reduce the urge to smoke, it may also reduce the urge to overeat. Although researchers arent yet sure of the mechanism of action responsible for this, people taking the drug report they feel satisfied with smaller amounts of food. What Is Rimonabant and How Might It Treat Obesity? Rimonabant is an experimental drug that appears to interfere with the effect often referred to as the munchies. Marijuana appears to stimulate an area of the brain that increases the appetite, resulting in intense cravings for large amounts of food. Rimonabant appears to depress this area of the brain and thereby interferes with food cravings.
Researchers wonder, but are not yet sure, if rimonabants appetite reducing effect could be harnessed for treating the compulsion to overeat. Researchers are also exploring the possibility that rimonabant may also help alcoholics curb their desire for alcohol. However, rimonabant is still experimental, and will require a great deal more testing before it could become available for use. Phase III trials (trials involving human subjects) are currently ongoing. Are These Drugs Safe? Research into the effectiveness of these agents for treating obesity continues. As far as safety is concerned, topiramate and zonisamide have a long history of safety for the treatment of epilepsy. In addition, bupropion has a long history of safety for the treatment of depression. Therefore, researchers believe these drugs will be relatively safe for treating obesity. Keep in mind, however, that all drugs have potential side effects and their use should be carefully monitored by a physician. Although doctors are free to prescribe topiramate, zonisamide, and bupropion for the treatment of obesity, the drugs are not currently labeled (or approved for use by the FDA) as weight loss agents. Consult with your doctor if you would like more information about the potential risks and benefits of using these drugs.
RESOURCES: American Obesity Association http://www.obesity.org National Institute of Diabetes and Digestive and Kidney Diseases http://www.niddk.nih.gov CANADIAN RESOURCES: College of Pharmacists of British Columbiahttp://www.bcpharmacists.org/youandyourpharmacist/ Health Canadahttp://www.hc-sc.gc.ca/index_e.html References: Anderson JW. Bupropion SR enhances weight loss: a 48-week double-blind, placebo-controlled trial. Obesity Research. 2002;10 (7)L:633641. Bray GA. A 6-month randomized, placebo-controlled, dose-ranging trial of topiramate for weight loss in obesity. Obesity Research. 2003; 11(6):722733. Gadde KM, Franciscy DM, Wagner R, et al. Zonisamide for weight loss in obese adults: a randomized controlled trial. JAMA. 2003;289:1820-1825. Kim CS. Zonisamide effective for weight loss in women. J Fam Pract. 2003: 52(8):600-601. Overweight, obesity threaten US health gains. US Food and Drug Administration website. Available at: http://www.fda.gov/. Accessed December 19, 2003.
Last reviewed March 2008 by Marcin Chwistek, MD Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
