The Consumer Healthcare Products Association, which represents U.S. manufacturers and distributors of over-the-counter medicines, says it's changing the labeling of the products to state "do not use" in children under four years of age. Current labels set the minimum age at two years.

"The steps that are being taken by CHPA will not affect the availability of the medicines, but this voluntary action will result in a transition period (during which) the instructions for use of some OTC cough and cold medicines in children will be different from others," the FDA said in a statement. The FDA said it usually doesn't request removal of OTC products during a voluntary label change.

"Therefore, some medicines will have the new recommendation 'do not use' for children under 4 years of age, while others will instruct that they not be used for children under 2 years of age," the federal agency said.

The FDA said it continues to recommend parents and caregivers do not give children medications labeled only for adults.