A popular diet pill is under scrutiny by the Food and Drug Administration. When orlistat was first introduced in 1999 it almost seemed too good to be true. This drug, known by the brand name Xenical, blocks the absorption of dietary fat from the digestive tract. Fat provides more calories per ounce than other foods, so this seemed like a wonderful way to have your cake and still lose weight. Certain side effects such as gas and oily discharge were widely publicized and provided grist for stand-up comics. But these embarrassing side effects did not keep the FDA from approving orlistat for over-the-counter sale as Alli in 2007.
Now the agency is taking a second look at the safety of orlistat. More than 30 cases of serious liver injury have been reported to FDA’s MedWatch program, and 6 patients using this drug have experienced life-threatening liver failure. The FDA has not yet determined if the drug is responsible, and it has not changed its recommendations for either prescription or over-the-counter use of orlistat. But it will be considering whether a warning is warranted for this weight loss drug.