What is Xenical®?

Xenical®,(orlistat) is a new weight control medication, just recently approve by the FDA, that has been widely tested throughout Europe. Distinct from other medicines that stimulate the brain to suppress appetite, Xenical® uses a fat blocking mode of action that works non-systematically in the gastrointestinal tract. The end result is approximately 30 percent of dietary fat passes through the body undigested.

How does Xenical® work?

Lipases, before they can be absorbed into the bloodstream. Xenical® interferes with these enzymes by forming covalent bonds with them in the stomach and small intestine, which essentially inactivates the enzymes so they are no longer available to hydrolyze dietary fat into an absorbable state. Thus allowing for approximately 30 percent of fat consumed in a meal to pass through the gastrointestinal system undigested.

What clinical studies have been completed?

Xenical® was evaluated in a placebo-controlled, double blind study to examine the effectiveness of a medication for weight loss and the prevention of weight regain over a two-year period.

During the first year, participants who met the definition of obese were placed on a low calorie diet while randomly given a placebo or orlistat. Research following the first year indicated those individuals treated with orlistat (120 mg per dose) lost approximately two-thirds more weight than the control (placebo) group.

In the second year, participants were placed on a weight maintenance diet and the orlistat group was randomized to receive either a placebo or different doses of orlistat. Results following the second year indicated the individuals on orlistat, 120 mg per dose, three times per day were two times as likely to keep the weight off as those individuals in the control (placebo) group.

"This study demonstrates that partial inhibition of fat absorption in obese subjects can produce sustained weight loss," the authors conclude. "Subjects treated with orlistat plus a mildly controlled-energy diet lost significantly more weight than those treated with placebo plus diet even though all subjects received a high standard of care and similar dietary counseling.These observations collectively suggest that orlistat may be a useful adjunct to dietary intervention in producing and maintaining weight loss over two years."

Journal of the American Medical Association (JAMA. 1999;281:235-242)

What are the side effects of Xenical?

Secondary to the mechanism of action, blocking the absorption of dietary fat, most individuals experience some changes in bowel habits. These changes may include gas with discharge, an increase in the frequency of bowel movements, fatty or oily stools and sometimes the inability to control bowel movements. These symptoms generally occur early in the treatment and subside in a relatively short period of time. Adhering to the recommended diet, meals that contain no greater than 30 percent of the calories from fat may significantly reduce any side effects.

Are there any other benefits to taking Xenical® other than weight reduction?

Yes, studies have shown that even a modest weight loss as a result of Xenical® and diet can significantly reduce the following life-risk factors:

• Reduction of blood glucose levels (decreasing the risk of diabetes)
• Lowering of diastolic and systolic blood pressure (decreasing the risk of heart disease and strokes)
• Reduction in blood cholesterol levels (decreasing the risk of heart disease and strokes)
• Reduction of blood levels of uric acid (decreasing the risk of gout)
• Reduction in the cases of sleep apnea (irregular breathing during sleep)

Weight reduction is also likely to improve appearance, which has a positive affect on self-esteem and motivation.

Which individuals benefit from Xenical®?

Xenical® is appropriate for those individuals who are considerably overweight, 30 percent above their ideal weight or a body mass index of 30 or greater. Xenical® may also be appropriate for those individuals who are overweight, 20 percent above their ideal weight or a body mass index of 27 or greater, and also have significant risk factors such as high blood pressure, high cholesterol or diabetes.

How does one determine their body mass index (BMI)?

BMI is calculated by dividing an individual's weight in kilograms by their height in meters squared.