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The Diet Drug Orlistat (XENICAL) and Gallstones

Worst Pills, Best Pills Newsletter article June, 2007

While conducting a routine postmarketing safety review of the diet drug orlistat (XENICAL), the Food and Drug Administration (FDA) recently stumbled upon an alarming finding: 37 cases of gallstones in patients of all ages between 1999 and 2006.

Public Citizen’s fight against orlistat
In May 1997, Public Citizen’s Health Research Group appeared before the FDA advisory committee that reviews diet drugs and argued against approval of orlistat unless there was evidence that it reduced the illness and death associated with chronic obesity. The drug has only been proven to marginally reduce weight, and that is not enough to justify approval, we argued. Nonetheless, the drug received a green light from the FDA; we listed it as a Do Not Use drug in the June 1999 Worst Pills, Best Pills News.

On April 10, 2006, Public Citizen petitioned the Food and Drug Administration (FDA) to immediately remove orlistat from the market because the drug can cause pre-cancerous changes called aberrant crypt foci in the lining of the intestines.

The FDA did not grant our petition. Instead, it approved an over-the-counter version of orlistat which will be available in late June, sold under the brand name ALLI.

What to Watch For
Symptoms of gallstones can occur suddenly. A typical attack can cause steady pain in the upper abdomen that increases rapidly and lasts from 30 minutes to several hours; pain in the back between the shoulder blades; pain under the right shoulder; and nausea or vomiting. Other gallstone symptoms include abdominal bloating, recurring intolerance of fatty foods, colic (acute abdominal pain), belching, gas and indigestion. Gallstone-related symptoms often follow fatty meals, and may occur during the night.

If, in addition to any of the above symptoms, you experience chills, low-grade fever, yellowish color of the skin or whites of the eyes or clay-colored stools, you should see a doctor right away.

In addition to gallstones, orlistat’s most common side effects are oily fecal spotting, gas with discharge, fecal urgency, fatty/oily stools and frequent bowel movements.

Orlistat works by preventing enzymes in the gastrointestinal tract from breaking down dietary fats into smaller molecules that can be absorbed by the body. Because orlistat reduces the absorption of some fat-soluble vitamins and beta-carotene, patients must take a supplement that contains fat-soluble vitamins (ADE and K) and beta-carotene.

What You Can Do
You should not take orlistat. There is no evidence that this drug can reduce the health risks associated with obesity. The drug’s minimal effectiveness for weight loss, coupled with the real risks of gallstones, vitamin deficiency and the occurrence of pre-cancerous lesions outweigh any benefit the drug might have. Clearly, this drug should come off the market immediately.