Weight Loss Drug Doesn't Work

Orlistat may cause kidney failure, liver damage and pancreatitis

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Some obese people take weight-loss drugs to help deal with their health problem. One of these drugs, orlistat, may be harmful.  The drug already carries a black box warning for liver damage, which the FDA added last year.

In a recent letter, the watchdog group Public Citizen asked the FDA to ban both prescription and over-the-counter versions of the weight-loss drug orlistat. Public Citizen believes there are more health risks than benefits in taking the drug.

"Orlistat may not help reduce weight."

The authors of the letter point to research that shows orlistat puts patients at risk of many health problems, while failing to help obese people lose enough weight to make a difference in their lives. While many doctors have stopped prescribing orlistat, there are still a great deal of patients taking the drugs.

Public Citizen said its own analysis of FDA adverse event reports found 47 cases of acute pancreatitis and 73 cases of kidney stones in patients receiving either the prescription or over-the-counter version of the drug.

Further, Public Citizen said orlistat works by inhibiting enzymes that break down fat, enabling it to be excreted instead of absorbed. This process, however, can prevent the absorption of certain fat-soluble vitamins, including vitamins A, D, E, and K.

In their letter to the FDA, the authors point to three phase III studies on Xenical (the prescription version of orlistat) and one study on Alli (the over-the-counter version) that showed that orlistat had little effect on patients' ability to lose weight. 

The studies also show numerous harmful effects caused by Xenical and Alli, including:

  • Severe liver injury - which can cause liver failure, the need for a liver transplant, and death
  • Acute pancreatitis - a condition that frequently puts people in the hospital and can lead to death
  • Acute renal failure (kidney failure)
  • Nephrolithiasis (kidney stones)

This request from Public Citizen comes at a time when obesity is a growing problem in the United States, costing the health care system billions of dollars.

In Depth

In their review of other studies, the authors also found:

  • 47 cases of acute pancreatitis
  • 73 cases of kidney stones in patients taking orlistat
Reviewed by: 
Review Date: 
April 20, 2011
Last Updated:
April 28, 2011