Orlistat (marketed as Xenical by Roche) is a drug designed to treat obesity. It works by inhibiting pancreatic lipase, an enzyme that breaks down fat in the intestine. Without this enzyme, fat from the diet is excreted undigested, and not absorbed by the body. more...
Orlistat is available on prescription, although, as with many prescription drugs, it is possible to obtain it from online pharmacies. In 2004, a lower-dose version of the drug (60 mg compared to 120 mg for the prescription dose) was released over the counter in Australia and New Zealand; the United States is expected to follow in the near future.
It has a number of side effects related to digestion. Because its main effect is to prevent dietary fat from being absorbed from the gut, the fat is excreted and so the stool becomes oily, runny, and gassy. Bowel movements may become frequent, urgent or uncontrollable. To minimize these effects, the fat content of the diet should be reduced to about 30%. Obviously many patients find these side effects uncomfortable, and this has resulted in serious compliance issues.
The drug should only be taken when there is fat in a meal (it will not work if there is no fat in the diet). Because some vitamins are fat soluble, the effect of Orlistat is to reduce their absorption. A multivitamin tablet containing these vitamins (D E K and beta-carotene) should be taken once a day, at least 2 hours before or after taking the drug.
The amount of weight loss achieved with Orlistat is quite modest. The weight loss in a 4-year double-blind trial averaged only 2.8 kilograms (about 6 pounds) more than placebo. Despite this cosmetically small effect, there was a 37% reduction in the incidence of diabetes, a medically very significant difference.
You must not take Xenical if you:
- have problems absorbing food
- have reduced gallbladder function
- are pregnant, or are still breast-feeding (it is not known whether Xenical is expressed in breast milk)
- have certain kidney problems (consult your doctor).
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