WASHINGTON — Children under 4 should not be given over-the-counter cough and cold remedies, drug companies said Tuesday in a concession to pediatricians who doubt the drugs work in kids and worry about their safety.

The voluntary changes came less than a week after federal health officials said they also saw little evidence that the drugs work, but feared that parents would give kids adult medicines if the products were taken off store shelves.

In addition, the drug makers said they will add a warning to their products that parents should not give children antihistamines to make them sleepy. These are allergy-relief medications often found in medicines that combine several ingredients to treat a variety of symptoms.

The new measures “reflect industry’s overall commitment to the continued safe and appropriate use of children’s oral OTC cough and cold medicines,” Linda Suydam, president of the Consumer Healthcare Products Association, said in announcing the changes on behalf of the companies.

“We are doing this voluntarily our of an abundance of caution,” she added. The new instructions will appear on products distributed for the coming cold season.

Pediatricians, who have been calling for a ban on marketing cough and cold remedies for children under 6, welcomed the shift by the industry.

“It’s a huge step forward,” said Dr. Joshua Sharfstein, Baltimore’s health commissioner. “There is no evidence that these products work in kids, and there is definitely evidence of serious side effects.”

Problems with OTC cough and cold medicines send some 7,000 children to hospital emergency rooms each year, with symptoms ranging from hives, to drowsiness, to unsteady walking. Many kids overdose by taking medicines when their parents aren’t looking.

Since a majority of the problems involve 2- to 3-year-olds, the industry’s new instructions, if followed by parents, should help.

“The 2- and 3-year-olds are definitely the highest risk,” said Sharfstein. “More than 50 percent of the problem is with these kids. “If they don’t have this stuff around the home, they’re less likely to grab it and ingest it.”

Pediatricians still support recalling the medicines for children under 6, and the Food and Drug Administration is studying their effectiveness for children under 12. But it could take a year or more for federal health officials to reach a final decision.

The industry is also expanding an educational campaign aimed getting parents to be more careful in giving their kids cough and cold medicines.

Parents are should never:

—Give adult medicines to a child.

—Give two or more medicines with the same ingredients at the same time.

—Give antihistamines to make a child sleepy.

Parents should:

—Give the exact recommended dose, using the measuring device that comes with the medicine.

—Keep OTC medicines out of sight and out of reach.

—Consult their doctor if they have any questions.