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Xenical and alli

Xenical 120 mg  

Hoffmann-LaRoche Web Sites

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Last updated October 27, 2007. Xenical (orlistat) is a drug that works locally in the gastrointestinal tract to inhibit the absorption of fat. It is a synthetic derivative of lipostatin, a naturally occurring lipase inhibitor ("fat blocker") which binds to gastric and pancreatic lipase, two digestive enzymes. Xenical also inhibits other digestive enzymes, including some found outside the gastrointestinal tract. When orlistat is taken with fat-containing foods, the fat passes through the gastrointestinal tract unchanged, and the calories are not absorbed. Pancreatic lipase reacts with the orlistat to reduce the absorption of about 30 percent of dietary fat, resulting in a reduction of approximately 200 calories per day. For patients who cannot take centrally acting appetite suppressants, Alli (prounced ally) is a half dose version of Xenical which was approved in 2007 for over-the-counter use.

Unfortunately, Xenical is associated with a lot of unpleasant side effects which include flatulence and abdominal cramps, fecal incontinence and oily spotting. Gastrointestinal (GI) side effects are the most common reason why patients discontinue this drug, and also why sales of Xenical have been less than anticipated even with additional approvals for its use in adolescent obesity and reduction in diabetes risk. The good news is that several second generation lipase inhibitors are in development. The most advanced of these compounds is cetilistat, which in extensive phase II testing has been shown to have a similar weight loss profile to Xenical -- without the GI side effects.


GSK Web sites

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OTC version Xenical approved. For patients interested in an over-the-counter (OTC) version of Xenical, the FDA approved Alli on February 7, 2007. The consumer health care group of GlaxoSmithKline acquired the rights in 2004 to market the reduced dose (60 mg) OTC formula.

  • FDA approves orlistat for over-the-counter use. FDA press release, February 7, 2007.
  • FDA Joint Advisory Committee recommends approval of orlistat 60 MG capsules for over-the-counter use. GlaxoSmithKline press release, January 23, 2005.
  • FDA Joint Advisory Committee sets date to review GlaxoSmithKline Consumer Healthcare’s proposal for Orlistat 60 (MG) capsules for over-the-counter use. GlaxoSmithKline press release, December 9, 2005.


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