The results echo recent research showing that a similar heartburn drug didn't work in adults with asthma.
Use of these heavily promoted acid-blocking drugs, called proton pump inhibitors, has more than doubled in U.S. children in recent years, but the study results suggest doctors should put the brakes on that practice, said University of Arizona asthma expert Dr. Fernando Martinez.
The study found children on prescription Prevacid pills had more colds, sore throats and bronchitis infections than those given dummy pills. There were also signs that children given Prevacid were prone to broken bones. That finding was weak and could have been due to chance. But Martinez said it is worrisome, given a Food and Drug Administration advisory about fracture risks in adults using these drugs long-term. And he urged "great caution" in prescribing these drugs to all children, not just those with asthma.
The study and an editorial by Martinez were released Tuesday in this week's Journal of the American Medical Association.
Acid reflux involves stomach acid backing up into the throat, causing irritation and often symptoms including heartburn. Asthma is an unrelated lung disease involving narrowed airways, with symptoms including wheezing, breathing difficulties and coughs. Sometimes acid reflux can cause similar respiratory symptoms and in children it often occurs without heartburn.
Some doctors believe that airway irritation caused by acid reflux may make asthma worse, and that undiagnosed acid reflux might be a reason why some people on standard asthma medicines continue to have symptoms. Prescribing acid-blocking drugs is thus common in people with poorly controlled asthma even if they have no obvious symptoms of reflux.
Previous research by some of the same study authors found that another acid-blocking drug, Nexium, didn't improve asthma symptoms in adults. Still, those drugs continue to be widely used in patients with asthma but no reflux symptoms, said Janet Holbrook, a researcher at Johns Hopkins' Bloomberg School of Public Health, lead author of the new children's study.
Holbrook said results from both studies likely apply to all proton pump inhibitor drugs, including those sold over the counter. Prevacid became available without a prescription during the study.
The new study involved about 300 children and teens at 19 centres whose asthma wasn't adequately controlled by steroid drugs. Half were given daily Prevacid pills for six months; the others received dummy pills.
Asthma symptoms didn't improve in either group. They also didn't improve in a subgroup of study kids who had airway tests that revealed undiagnosed reflux disease, Holbrook said.
Bronchitis was twice as common in kids on Prevacid, and they were also 30 per cent more likely than the others to develop colds and sore throats.
It's unclear if those symptoms were caused by the reflux drug. But it's possible that these drugs interfere with helpful bacteria in the body that fight infection, said Dr. Chitra Dinakar, an asthma specialist at Children's Mercy Hospitals and Clinics in Kansas City, Mo. who took part in the study
Dinakar said she will no longer be inclined to prescribe powerful acid-blocking drugs for kids with asthma but no obvious signs of reflux.
Dr. Daniel Searing, an allergy and asthma specialist at National Jewish Health in Denver, said the study provides important information to pediatricians wondering if the previous study in adults was applicable to children.
The National Institutes of Health and American Lung Association paid for the study.
AP Medical Writer Lindsey Tanner can be reached at http://www.twitter.com/LindseyTanner