The U.S. Food and Drug Administration (FDA) is warning healthcare professionals and consumers about potential rare occurrences of severe liver injury associated with taking the weight loss drug orlistat, which is marketed under the brand names of Xenical and Alli.

The FDA has approved a revised label for the prescription drug Xenical. The agency is working with the manufacturer of Alli, which is sold over-the-counter, on label revisions to reflect this rare occurrence.

Symptoms of liver injury may include itching, yellow eyes or skin, dark urine, light-colored stools or loss of appetite.

The agency has identified 13 cases of severe liver injury, 12 of which were reports from outside of the U.S.

The FDA says that at this time, a cause-and-effect relationship of severe liver injury with orlistat use has not been established.
An estimated 40 million people worldwide have taken either Xenical or Alli.

In addition to limiting calories and increasing physical activity, some health practitioners have suggested the alkaline diet for those trying to shed extra pounds. It is based on citrus fruits, vegetables, tubers, nuts and legumes.