Among side effects, Xenical can cause soft stools and oily leakages as the pill sends undigested fat out of the body so it doesn't wind up instead on dieters' thighs. Xenical also can decrease absorption of vitamin D and certain other important nutrients, the panel warned. They unanimously recommended that Xenical users take carefully controlled doses of vitamin supplements. The FDA isn't bound by advisory panel decisions but typically follows them. Metabolic drug chief Dr. James Bilstad said the agency would make a decision within a month.
Dieters have a variety of appetite suppressants that offer modest help.
A similar competitor, Knoll Pharmaceuticals' sibutramine, is expected to be approved within the year. Xenical, known chemically as orlistat, would become the first drug to fight obesity through the intestine instead of the brain. The drug, taken with each meal, binds to certain pancreatic enzymes to block digestion of 30 percent of the fat people eat. If Xenical is sold, no one should combine it with Redux or other appetite suppressants because there is no research to date showing that would be safe, warned Roche scientist Dr. Russell Ellison. The FDA is evaluating how strongly to warn consumers and doctors about that issue, Bilstad said.