A NEW study released this week sends out a strongly worded warning about risks of kidney, liver, and other organ damage from the most popular weight drugs on the market.
According to a University of Rhode Island study funded by the National Institutes of Health (NIH), orlistat, which goes by the prescription brand name Xenical and the over-the-counter name Alli, can cause “severe toxicity” to major internal organs.
The research results obtained by pharmacology professor Bingfan Yan were worrying enough that he immediately reported the results to the FDA, which approved orlistat aka Alli in 1999.
Liver and kidney damage are serious enough, but Yan’s team also reported another finding, just as concerning, that orlistat’s metabolic action reduces the effectiveness of many medications, including life-saving cancer treatments. In fact, the researchers reported that cancer cells multiplied faster under the influence of orlistat. Orlistat also boosts the anti-clotting effects of aspirin, raising the risk of bleeding both internal and external.
Yan and his team found that orlistat – even at low doses – limits the function of a key enzyme called carboxylesterase-2, which has an important role in detoxifying the liver, kidneys, and entire gastrointestinal tract. Preventing this enzyme from doing its job, the report says, may result in “severe toxicity of internal organs.”
In May 2010, the FDA announced a new consumer warning for Xenical/Alli indicating the potential for liver toxicity. However, the wording of the warning describes “rare reports” of liver damage, which is certainly milder than suggested by the new study. According to FDA data, the agency counted just 13 cases of severe liver damage, 1 in the U.S. and 12 in other countries. The information on orlistat’s potential toxicity to the kidneys, other organs, and gastrointestinal tract in general is new.
Yan is a highly respected pharmacologist noted for his discoveries of dangerous drug interactions and an author (among several) of the Encyclopedia of Drug Metabolism and Interactions.
Since orlistat became available over the counter as Alli in 2007, its popularity has increased enormously.
Two new weight loss drugs, Belviq (lorcaserin) and Qnexa, have come on the market this year, lorcaserin and Qnexa, each with its potential benefits and health risks. So far, it doesn’t seem possible to interfere with the body’s fat absorption mechanisms without some sort of downside.