Doctors, patients and the Food and Drug Administration (FDA) need to exercise more caution when it comes to using new drugs, concludes a study led by several Harvard Medical School professors.

Published yesterday in the Journal of the American Medical Association, the study finds that one in five new prescription drugs approved by the FDA in the last 25 years were later withdrawn or restricted from the market after doctors identified adverse health risks to patients.

“We looked at all drugs produced in the last 25 years, and for 20 percent of them, doctors later identified life threatening side effects,” said Stephanie J. Woolhandler, an associate professor of medicine involved with the study.

According to the results, half of these effects appeared within two years of a drug’s approval, while the rest appeared within seven.

“We took data from the drug industry itself,” she said, referring to the Physician’s Desk Reference, an FDA-approved guide that includes information on prescription drugs. The study is unique in analyzing changes in the guide in an attempt to evaluate drug approval processes.

Woolhandler said the results are an indication that doctors “don’t have their antennae up for complications,” adding that it is impossible to know the safety of new drugs because they haven’t been tested by years of use. The study notes that most new drugs are often only studied for limited periods before they are approved.

Woolhandler said that in a few cases, the FDA has even approved new drugs although some pre-marketing studies indicate potential complications with the drugs, dismissing the evidence as coincidence.

Sidney Wolfe, co-author of the study and director of the Public Citizen Health Research Group, alleged that “the FDA is at an all time low as far as the drug approval process.”

Woolhandler and Wolfe, who has spent 31 years conducting research aimed at protecting patients, both urged more caution with regard to new drugs.

Woolhandler called on the FDA to be much more careful when approving new drugs.

But Wolfe emphasized the role of patients and doctors.

“Don’t use new drugs, unless they represent an important medical advance,” he said.

But even in such cases, Woolhandler said, those drugs should be used carefully, with careful monitoring for side effects.

The study also has significant economic implications for the drug industry, which, according to Woolhandler, spends billions of dollars promoting new drugs to patients and doctors.

“In order to maximize profits,” she said, “the drug industry needs to sell the newest drugs.”

Wolfe also suggested that the FDA has financial incentives to approve new drugs—the drug industry’s profits are directly funneled to the FDA as a result of the Prescription Drug User Fee Act of 1992, he said. Wolfe added that the act will be up for reauthorization soon.

Meanwhile, Woolhandler cautioned patients against needlessly spending large amounts of money on new drugs that can be dangerous.

“If everyone followed the advice of this study, the result would be huge consumer savings,” she said.