It plans to pull about 500 ineffective prescription drugs off the market. The FDA requires companies to submit all new prescription drugs for scientific review before they are launched.
However, thousands of drugs predate those regulations, so they've escaped scrutiny. Most of the drugs targeted by the latest action are pills using untested combinations of decongestant and cough-suppressing ingredients. FDA's action does not affect any products sold over the counter.
Doctors may not realize they are prescribing unapproved drugs because the products are often labeled just like FDA-approved products, according to the agency. Many of the older drugs cited by the FDA are manufactured by multiple companies, often using different ingredients and dosages.
"That's what makes them so dangerous: they have these shared names but different ingredients and different doses, so it's very easy for medication errors to occur," said Patti Gasdek Manolakis, a pharmacist and consultant who has researched unapproved drugs in the U.S.
The FDA said it doesn't expect the crackdown to have a negative impact on consumers.
The Associated Press contributed to this story