The doctor knows best, right?

Maybe not, according to new research from a University of Chicago Medical Center professor.

Dr. G. Caleb Alexander, an assistant professor of medicine, found that a surprising number of physicians do not know if many medications have been approved by the Food and Drug Administration. Alexander and his fellow researchers, in an article published Friday in the journal Pharmacoepidemiology and Drug Safety, wrote that some physicians will prescribe medication they mistakenly believe to be FDA-approved.

“Off-label prescribing is common, but researchers have not always known why,” Alexander said in a statement. “Our research shows that some off-label prescribing might be driven by mistaken beliefs about FDA approval and the level of evidence supporting off-label drug use.”

In a survey of more than 1,100 physicians and psychiatrists, respondents were able to correctly identify the FDA-approval status of just over half of the 22 medications included in the survey. Alexander says the results are proof physicians should be more careful about what they prescribe, especially if the drugs are ineffective or risky.

The FDA regulates the marketing of medication, not the prescription of drugs. Past research has shown that nearly a quarter of prescriptions in the United States are of “off-label” medications, and 73 percent of those drugs lacked scientific evidence of their efficacy.

“We hope our research will increase awareness of off-label prescribing and highlight the pressing need for more evidence-based use of prescriptions drugs,” Alexander says. “Although some off-label uses are well-supported, many are not. New ways are needed to help physicians tap the scientific evidence supporting various prescriptions drug uses.”