Changes made by makers of cold and cough medicines in 2007 have resulted in a significant decrease in visits by infants and toddlers to hospital emergency rooms due to these medicines, according to a new study.

Drug makers voluntarily withdrew infant cold and cough medicines intended for children under age 2 from the market in 2007, and made changes in labeling on other products warning parents they should not be given to children under 4, The New York Times reports.

The study, conducted by researchers at the Centers for Disease Control and Prevention, included data from 63 hospitals. The study estimated the number of visits to emergency rooms from 2004 to 2011 by young children who had taken cold and cough medicine. Before the 2007 changes, children under 2 accounted for 4.1 percent of emergency room visits for suspected drug-related effects. After the change, they accounted for 2.4 percent of the visits.

Among children ages 2 to 3, ER visits related to cold and cough medicines dropped from 9.5 percent before the changes took effect, to 6.5 percent afterwards. There was no significant reduction in ER visits among children 4 to 11. Among children ages 4 and 5, visits related to cold and cough medicines increased from 5.6 percent to 6.5 percent.

“We’re making great progress in under-2s, and we’re making relatively good progress in 2 to 3s,” said Dr. Don Shifrin, a spokesman for the American Academy of Pediatrics. “But we’d like better news for kids over 4.”

Most infants and toddlers who end up in the ER for problems related to cold and cough medicines got hold of the medicines when a parent’s back was turned, the article notes. “Of adverse events still occurring, 90 percent in 2- to 3-year-olds were unsupervised ingestions,” said study senior author Dr. Daniel S. Budnitz.

The findings are published in Pediatrics.