Get the latest updates as we post them — right on your browser

. Last Updated: 07/27/2016

Cholesterol Drugs Found Cancer-Causing in Study

LOS ANGELES -- The world's most widely used cholesterol-lowering drugs cause cancer in laboratory animals, say researchers at University of California, San Francisco, in a hotly disputed new study warning that the drugs also may cause cancer in human beings.

The researchers' analysis covered two broad classes of anti-cholesterol medications, the so-called statins and fibrates. Among them are the industry-leading lovastatin, or Mevacor, and gemfibrozil, or Lopid.

Using drug-testing data in the Physicians' Desk Reference, U.S. Food and Drug Administration records and other sources, the researchers say they found what one called "underdiscussed" evidence that mice and rats develop tumors in response to large doses of the drugs.

While the FDA approved the drugs years ago, their cancer-causing potential has been neglected in part because they reduce heart-disease deaths so effectively in people who have had a heart attack or who have extremely high blood cholesterol levels, the researchers say.

"We have to be careful about getting so enthusiastic about drug treatment that we say these things are wonderful and everyone should be on them," said Dr. Thomas Newman of UCSF, who wrote the paper with Dr. Stephen Hulley. It appears in Wednesday's Journal of the American Medical Association.

In an unusual move, the same AMA journal carries an editorial disputing the new analysis. It says that laboratory rodents are more susceptible to cancer than people are, that the drugs were tested at extremely high doses never encountered by people, and that large clinical trials of the drugs have failed to turn up an excess of cancer. Drs. James Dalen and William Dalton of the University of Arizona College of Medicine said the UCSF researchers "have not presented convincing evidence that cholesterol-lowering by diet or drugs increases the risk of cancer deaths."