The FDA issued a statement reporting 13 cases of liver damage apparently linked to a popular diet drug.  orlistat is sold as prescription Xenical and over-the-counter Alli, both manufactured by GlaxoSmithKline.

Initially, the FDA was alerted to 32 cases of liver damage in August of 2009; however, it is likely that the reason for the decrease is that only 13 of those cases could unequivocally be attributed to the weight loss drug (HealthDay).

Orlistat is taken by 40 million people worldwide; only 2 of the 13 cases of liver injury were in the United States, illustrating how rare the occurrence is.

From the beginning, sales of the drug have been steadily increasing. After only four months on the market, Glaxo sold more than 2 million, 90-day starter packs.  The company announced in 2007 that it expected 5-6 million people a year to use the product.

At the time of Alli’s debut on the OTC market, Glaxo was praised by analysts for the unique way the product was marketed.  Although they touted it as a weight loss drug, the company did not recommend  it to dieters unless they had been put on a restricted diet.  In other words, they emphasized that portion control is essential for the drug to work.

Orlistat works by blocking the absorption of fat in the intestine.  In a study taken after its introduction to the market, half of dieters who took Alli in tandem with a diet and exercise program lost 5 percent or more in body fat after six months (New York Times).