Twenty percent of new drugs later found to have serious adverse effects

The May 1 2002 issue of the Journal of the American Medical Association reported the results of a study that sought to determine the frequency of previously unrecognized adverse drug reactions occurring in recently approved drugs. By analyzing volumes of the Physician's Desk Reference published over a twenty-five year period as well as other information, researchers at Harvard University discovered that half of the newly established adverse effects, which include liver, bone marrow and heart damage as well as pregnancy risks, are found within seven years of their approval, and half of the drugs withdrawn were taken off the market within two years following their release. Study author and primary care physician and researcher at Cambridge Hospital and Harvard Medical School, Dr Karen Lasser, stated, "This study will change the way I talk to patients about the use of new drugs. If there is a safer, effective drug that has been in use for a number of years, I would strongly recommend it over a newer drug whose safety profile is unknown. I would prescribe a new drug only when absolutely necessary, and then watch for adverse effects very, very closely."

The authors attribute the widespread use of new drugs to extensive promotion by pharmaceutical companies. They note that drug companies may fail to conduct the postmarketing studies the Food and Drug Administration requires when a safety issue is discovered during the drug's preapproval phase.

Coauthor Dr. Paul Allen , an internal medicine specialist at Cambridge Hospital and Harvard Medical School, commented, "Twenty million patients, almost 10 percent of the U.S. population, were exposed to the five drugs withdrawn from the market between September 1997 and September 1998. Yet the drug companies push the public and doctors to use new drugs that are more profitable but also more dangerous."