Orlistat - a Medication for Obesity Treatment and Weight Maintenance
Orlistat (brand name Xenical) is a medication approved for obesity management and is available in most countries, including the U.S. It should be used as an adjunct to diet and exercise in the treatment of obesity. When one eats a "normal" meal, one consumes carbohydrates, proteins, and fat. Many people who are obese consume a diet that is relatively high in fat. In fact, the body's ability to convert carbohydrates or protein to fat is limited in that the conversion process requires a significant proportion of the energy that is contained in the food. Thus, much of the excess body fat found in obesity results not from de novo (new) synthesis of fat from other nutrients but from the fat that is consumed in the diet. Since fat contains more than twice as many calories per gram as do protein and carbohydrates (9 calories per gram of fat verses about 4 calories per gram of carbohydrate or protein), reducing fat intake is critical to reducing body weight. If you are trying to lose weight, you should reduce your fat intake.Mechanism of action
Orlistat interferes with fat absorption. Digestive juices produced by the liver and pancreas in response to food are secreted into the intestine which leads to absorption of nutrients. Two of these secreted substances are called gastric and pancreatic lipase which are used to digest fat. Orlistat inhibits the lipase that is secreted into the intestine. Only minute amounts of orlistat are absorbed into the bloodstream; thus the medication acts non-systemically and has an excellent safety profile. When the drug is consumed with a meal, some of the fat (about 30%) from the meal passes out of the body in the stool. Thus some of the calories consumed are not absorbed and are "wasted" in the stool.Clinical results
Clinical trials involving orlistat when used in conjunction with diet and exercise have been shown that the average patient will lose about 10% of their initial body weight. The average weight loss that is attributed to the medication averages about 7.5 lb. (approximately 3.5 kg). Most patients in a 24 month study tolerated the medication fairly well. Side effects included oily stools, oily spotting, fecal urgency, and increased defecation, and occasional fecal incontinence (when first starting the medication). All of these side-effects worsen as the amount of fat in a meal increases; thus it is recommended that the diet be limited to no more than 30 % fat and that the fat be dispersed in three daily meals. Also, since certain vitamins are fat soluble (notably A, D, E, & K), the levels of these vitamins may fall slightly but (generally) remain within the normal range. It is recommended that individuals take a vitamin supplement to prevent possible vitamin deficiency (especially if the medication is used long term). An important added bonus with orlistat is that cholesterol levels generally fall (elevated cholesterol is a frequent complication of obesity) with the average person's cholesterol dropping by about 8 - 10 %.Who should avoid using this medication?
Individuals who have binge eating disorder probably should not be placed on this medication since they will probably have significant gastrointestinal "distress" and fecal incontinence resulting from their binge eating episodes. On the same note, individuals with bulimia nervosa should not be placed on this medication. Several other less common problems (e.g., malabsorption syndromes) will preclude individuals from utilizing this medication. Like all medical treatment, the decision to use a particular medication should be made jointly with your treating physician.
Is Orlistat the same as Chitosan?
Chitosan is a substance that is derived from shellfish exoskeletons (the "shell" of the shellfish) that promoters state will block fat absorption. Unfortunately, the amount of fat absorption that is blocked by chitosan is minimal and of no significant benefit. Thus you can see that the prescription drug Orlistat is NOT the same as chitosan.
Does the weight keep going down with Orlistat after the first year?
Generally, the weight stabilizes but doesn't go down further.
Conclusion
Orlistat, although not a miracle, should prove to be a useful as part of a comprehensive treatment plan in the management of obesity. It may be particularly useful in assisting with weight maintenance after successful weight reduction.
Last modified: August 2001.Copyright © 1996 -2001
Michael D. Myers M.D. Inc.
All rights reserved.
The above information is for general purposes only and should not be construed as definitive or binding medical advice. Because each person is medically different, individuals should consult their own personal physicians for specific information and/or treatment recommendations.