The prescription diet drug Xenical hits drugstore shelves with a new name and in nonprescription strength on Friday. Most of the buzz around this reincarnation, dubbed Alli, centers on its effectiveness and its less pleasurable side effects, like oily stools and gas with oily discharge.

But one group has worked unsuccessfully for the past year to bring attention to what it believes is a worse, and possibly fatal, side effect of the drug.

The nonprofit group, Public Citizen says Alli, manufactured by GlaxoSmithKline, has been shown in studies to cause pre-cancerous lesions in the colons of mice. And, because there are no long-term studies of the drug’s effect on humans, the group believes the U.S. Food and Drug Administration should not have approved the drug for nonprescription use.

Dr. Sidney M. Wolfe, director of Public Citizen’s Health Research Group, said, while it is not known whether these pre-cancerous lesions will lead to colon cancer, he and other cancer experts do not believe use of the weight-loss drug is a risk worth taking.

"What we do know is that these lesions occur much more frequently in people who do get colon cancer," he said. "Why do we recommend that everyone get a colonscopy at the age of 50? Because you pick up on these polyps when you do one. And, even though not all of the polyps are pre-cancerous, no (doctor) does a colonscopy without removing every single polyp that is found. And you do this because you know if you don't, it greatly increases the chances of getting cancer."

But the FDA, in a response to Public Citizen earlier this year, said there was not enough evidence to link Alli to colorectal cancer, nor was their evidence to link the drug to breast cancer, another concern raised by Public Citizen.

“We conclude that the available evidence concerning orlistat's safety does not support a causal relationship between orlistat and colorectal carcinoma, nor does any of this information meet the criteria for market withdrawal,” the FDA wrote in its decision.

FDA Approval

The FDA approved the weight-loss drug, Xenical (orlistat), in the prescription strength of 120 mg in April 1999. The FDA required pharmaceutical company Roche, the maker of Xenical, to monitor the drug for a possible link to breast cancer until 2000. Roche satisfied this requirement and a link to breast cancer was never proven, according to the FDA.

The FDA approved orlistat, to be sold under the brand name Alli, for over-the-counter use for people 18 and older in February of this year. The drug will be sold in 60 mg capsules, half of the prescription dose.

But Public Interest said Roche’s own study, as well as a study by an independent researcher, shows a link between pre-cancerous colon polyps and orlistat, and called the FDA’s approval of the drug for over-the-counter use as the “height of recklessness.”

The FDA did not respond to a request for an interview.

Does Alli Work?

Alli decreases the amount of fat absorbed by the body. In addition to causing loose and oily stools and unfortunate and uncontrollable oily discharge, the drug may also interfere with the absorption of the fat-soluble vitamins A, D, K and E. It is recommended that people taking Alli also take a multivitamin.

While Alli has been shown to help people following a healthy diet lose weight, studies show that consumers should not expect dramatic results from taking the drug. The retail price for Alli is $49.95 for a starter package of 60, $64.95 for a starter package of 90, and $76.95 for the refill package of 120 capsules.

Last fall, Dr. James Anderson, head of the UK College of Medicine Metabolic Research Group, and his colleagues examined the effects of 60 mg orlistat on mildly to moderately overweight individuals. Previous studies only looked at the drug’s effect on obese people.

Study participants took orlistat or a placebo three times daily with meals for 16 weeks. "Our research showed that people taking orlistat and following low-fat diets lost almost 5 percent of their initial body weight, about seven to 15 pounds over four months," Anderson said in a press release.

But Wolfe called the drug a failure and said prescription sales of the drug have lagged, which is why Roche made a deal with Glaxo to market the drug over the counter.

"First of all, the drug doesn't work unless you have a certain amount of fat in your diet," he said. "Most people that are on low-fat diets are eating a lot of carbohydrates. Well, Alli doesn't block carbohydrates. On the other-hand, if you are eating a lot of fat in your diet, you're going to end up saying to yourself, 'I thought I was already toilet trained' because 25 percent of the people use this drug get oily spotting."

Anderson acknowledged that a weight loss of two to four pounds a month “isn’t dramatic,” but said steady weight loss can have major health benefits. “For example, the reduction in LDL-cholesterol, the bad-guy cholesterol, of 10 percent can reduce risk of heart attack by 20 percent," he added.

But Wolfe disagreed and said the overweight people would do better to follow a healthy diet and exercising.

"The bottom line is that we have a public despearate for quick fixes in weight loss," said Wolfe. "But there is no magic pill to fix something that needs to be fixed slowly and chronically. If you go on a low-fat diet with Alli, you're probably going to lose seven-and-a-half pounds a month, compared to 5 pounds without it. But the studies also show that once you stop the drug, you regain the weight."