Orlistat (Xenical), which was approved by the FDA in April 1999, is the first prescription drug in a new class of anti-obesity drugs that works by blocking the body’s absorption of dietary fat.
Orlistat (Xenical) works in the gastrointestinal tract, blocking an enzyme that is needed to digest fat. Instead of being absorbed into the body, up to one third of the fat that a person consumes will accumulate in the intestines and be excreted in the stool. Orlistat (Xenical) also blocks the absorption of needed fat-soluble vitamins A, D, E, and K, as well as beta-carotene, so daily vitamin supplements must be taken.
Orlistat (Xenical) Side Effects
Orlistat’s most commonly reported side effects include bloating, diarrhea, and oily stools.
In one clinical trial involving Orlistat (Xenical), patients who took the drug and followed a weight-loss diet for one year lost an average of 19.3 pounds, while those who followed the diet and took a placebo lost an average of 12.8 pounds. Patients who took Orlistat (Xenical) also showed improvements in high blood pressure, high cholesterol and diabetes, according to the drug’s manufacturer, Hoffman-La Roche.
The makers of Xenical claim that it reduces the amount of fat that can be absorbed into the bloodstream by up to thirty percent. This corresponds to about 600 calories a day, which should lead to a weight loss of about 1 pound a week.
Xenical Needs Low Fat Diet
Because excess fat goes straight through the body when Xenical is taken, dieters are advised to eat a low-fat diet otherwise they can get diarrhea.