TUESDAY, Aug. 25, 2009 (HealthDay News) -- As U.S. health officials announced Monday that they are investigating the weight-loss drug orlistat for possible incidents of liver damage, experts noted the drug might not even work well enough to warrant such potential risks.
Orlistat is available in the United States, both as a prescription product (Xenical) and as an over-the-counter medication (Alli).
Depending on the findings from the investigation, this could dramatically change the risk-benefit ratio of taking the drug, experts noted.
The weight loss gleaned from the drug is quite modest, about 5 kilograms, said Dr. Timothy Pfanner, an assistant professor of internal medicine at the Texas A&M Health Science Center College of Medicine and a gastroenterologist with Scott & White, in Temple, Texas.
"It's not a really effective drug. The benefit is not so great to begin with," he said, and additional risks might simply make the drug that much less attractive.
The other problem is that many obese people already have underlying liver problems, added Dr. Eugene Schiff, director of the Center for Liver Diseases at the University of Miami Miller School of Medicine.
"If they [the Food and Drug Administration] feel there is a subgroup, albeit a small one but a real one, that gets a serious liver injury, [that] often will be compounded by the fact they have underlying liver disease," he said. "It's very important that this be resolved quickly."
The issue is complicated by the fact that some patients are taking the drug in its over-the-counter form, meaning they are likely not being tracked and monitored by doctors for side effects.
At this point, there is no reason for consumers to stop taking the drug if they're already on it -- as long as they're using it as recommended -- and no reason for physicians to stop prescribing it, U.S. Food and Drug Administration officials stressed Monday.
But the agency does recommend that patients tell their doctor if they are having symptoms such as weakness, fatigue, fever, jaundice or brown urine. Abdominal pain, nausea, vomiting, light-colored stools, itching and loss of appetite might also signal trouble.
Monday's move follows reports of 32 cases of serious liver injury, including six cases of liver failure, between 1999 and October of 2008.
More commonly, patients reported having jaundice, weakness and abdominal pain. For 27 patients, the symptoms were severe enough to require hospitalization.
Two of the cases occurred in the United States, the rest originated overseas.
In 10 years of being on the market, this isn't a great number, Pfanner noted.
The Drug Safety Oversight Board, part of FDA's Center for Drug Evaluation and Research, first looked into the issue in April. The agency stressed that there is no established association or evidence of a cause-and-effect relationship at this time.
The FDA first approved orlistat as a prescription medicine in 1999. In 2007, it became the first nonprescription drug approved to treat obesity in American adults.
The prescription version of the drug comes in 120-milligram capsules while the over-the-counter version is available in 60-milligram pills. Both versions are designed only to be used in conjunction with a reduced-calorie, low-fat diet by overweight adults aged 18 and older.
In 2006, the consumer advocacy group Public Citizen petitioned the FDA to remove Xenical from the U.S. market, not because of liver-related issues but because it might increase the risk of aberrant crypt foci, believed to be precursors to colon cancer.
The FDA's approval of the first over-the-counter drug for weight loss came as the United States and other western nations are struggling with an unprecedented obesity epidemic.
According to the U.S. National Center for Health Statistics, 30 percent of American adults aged 20 and older -- more than 60 million people -- are obese. Another 36 percent are considered overweight.
Orlistat is also approved in some 100 countries, with an over-the-counter form available in the European Union.
The U.S. National Library of Medicine has more on orlistat.