The weight loss drugs Alli and Xenical should be removed from the market because of the growing risk of side effects that include liver damage, pancreatitis and kidney stones, according to the consumer watchdog Public Citizen.
In a new attempt to eliminate the only FDA-approved class of weight-loss drugs, Public Citizen issued a petition to the U.S. Food and Drug Administration Thursday -- its second in five years -- calling for the agency to ban the class of drugs called orlistat, better known by the prescription brand names Xenical and Alli.
"These drugs have the potential to cause significant damage to multiple critical organs, yet they provide meager benefits in reducing weight loss in obese and overweight patients," said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group.
An estimated 40 million people worldwide have taken either Xenical or Alli in the last decade. But sales have decreased substantially over the last decade. Alli sales dropped from $145 million in 2007 to $84 million by mid-2010, according to a report released by Public Citizen.
The drugs' maker, GlaxoSmithKline, announced Thursday it is trying to sell the brands.
Breakthrough Drug that Fizzled
In 1999, Xenical, sold by prescription, was touted as a breakthrough weight-loss drug. Alli was approved in 2007 as an over-the-counter drug. The FDA banned the two market-leading pills, Fen-phen and ephedra, because of potentially fatal side effects.
Studies suggest that taking Xenical or Alli would only help people lose 4 to 6 pounds more than they would with only diet and exercise.
"The benefit was never that great, but many people thought they'd take their chances," said Wolfe.
Drugs Block Fat Enzymes
The drugs work by blocking absorption of about a third of certain protein enzymes that enter the body. Instead, the fat passes through the body to the gastrointestinal tract until it is excreted. These medications also block fat-soluble vitamins including vitamins A, B, and K.
Some of the more common side effects of Alli or Xenical include diarrhea and stool leakage.
However, according to Dr. Donald Hensrud, associate professor of nutrition and preventive medicine at the Mayo Clinic in Rochester, Minn., the longer a patient stays on the medication, the more likely these symptoms will go away.
"The chances of having those side effects are a bit overrated," said Hensrud. "Only about 20 percent of people get those side effects, and in most people it lasts for less than a week."
More severe side effects reported to the FDA include liver disease, pancreatitis, and kidney stones. The FDA received 47 reports of acute pancreatitis and 73 cases of kidney stones attributed to orlistats.
While many experts say these side effects are rare, it's not clear what segment of people who use the drug may experience these severe conditions.
Monique Paulwell of Bowie, Md. said she only took Alli four times before she began feeling fatigue, loss of appetite, a nagging headache and jaundice.
"After a battery of tests, [doctors] said there had been an attack on my liver," said Paulwell. "By the time I was admitted to the hospital, I had 48 hours to live. It was that serious."