The Food and Drug Administration has made a controversial policy change that will allow pharmaceutical companies to market unapproved, or "off-label," uses of drugs. The policy, coming in the form of a guidance document, will allow industry representatives to use journal studies to persuade doctors to prescribe FDA-approved drugs for unapproved uses. More from Reuters:

By law, manufacturers are prohibited from marketing their medicines for uses not approved by the FDA. But doctors can prescribe drugs for any use they see fit, a practice known as "off-label" use.

Distribution of medical literature suggesting a drug may have merit for an unapproved use is a marketing area that has been in dispute for years.

The FDA guidance allows drug companies to circumvent the law: now, the journal articles can do the talking.

FDA observers are critical of the new policy. Critics say the studies industry circulates can come from second-rate medical journals and may not have undergone rigorous scientific review. Prescribing drugs for unapproved uses can be a venture into the unknown. Will the patient benefit from the drug? Will there be unknown side effects?

The issue may seem esoteric, but critics are not just splitting hairs. Off-label prescription is big business. Again, Reuters: "About one of five prescriptions in the United States was written to treat a condition for which the drug was not approved, according to a 2006 study published in the Archives of Internal Medicine. The researchers said most off-label use occurs without scientific support."

And more from Merrill Goozner at the GoozNews blog: "More than half the drugs prescribed in oncology are for off-label indications, often based on studies that appeared only in the medical literature and never submitted to the FDA."

Industry had been pushing FDA to finalize the guidance, according to an investigation by the House Oversight and Government Reform Committee. (More here.)