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The Power of Blinded Research: Asthma and Acetaminophen

Study shows acetaminophen can be tolerated by children with mild, persistent asthma

Innovations in Pediatrics - Winter 2017


Clinical Director, Division of Pediatric Pulmonology, Allergy/Immunology and Sleep Medicine, UH Rainbow Babies & Children’s Hospital; Associate Professor of Pediatrics, Case Western Reserve University School of Medicine

Acetaminophen is the most commonly used fever and pain reducing medication for young children. In the last few years, some pediatricians began to recommend against its use for children with asthma, citing the findings of several observational studies that suggested it increased the risk of asthma exacerbations. 

The National Heart, Lung, and Blood Institute’s AsthmaNet network funded a randomized, controlled study to find out for certain if this was the case. The study, published in the New England Journal of Medicine, found no differences in the number or severity of asthma flares-ups in children using either acetaminophen or ibuprofen to reduce fever and pain.

“Before this study, some research suggested that there might be an association between using acetaminophen and asthma flares, but no high quality studies proved it was the acetaminophen itself that led to increased symptoms,” says Kristie Ross, MD, MS, Clinical Director, Division of Pediatric Pulmonology, Allergy/Immunology and Sleep Medicine at University Hospitals Rainbow Babies & Children’s Hospital and Associate Professor of Pediatrics at Case Western Reserve University School of Medicine, who co-authored the study with AsthmaNet colleagues around the country, including UH Rainbow pediatric pulmonologists James Chmiel, MD, MPH, Professor of Pediatrics, and Ross Myers, MD, Assistant Professor of Pediatrics. “It isn’t always possible to do a rigorous, blinded and controlled study to test whether an association is valid, but when we can, as in this case, we should.”

AsthmaNet investigators studied 300 children, ages 1 to 5, who had mild, persistent asthma requiring daily, inhaled treatments to manage it. During the study, caregivers were randomly assigned to use either acetaminophen or ibuprofen at standard doses when a child needed pain or fever relief. None of the study investigators, children or caregivers knew which study drug each child was receiving.

The study did not find any worsening of asthma in the children treated with acetaminophen compared with those receiving ibuprofen, as measured by the rate of asthma flares, number of days with no asthma symptoms, the need for rescue or quick relief medications, and the need to seek medical attention for worsening asthma. There was also no significant difference in safety between the two drugs. The investigation focused specifically on the question of whether administering acetaminophen for pain and fever to young children with a history of mild asthma will worsen asthma symptoms compared with ibuprofen. It did not look at the relationship between acetaminophen exposure early in life and the later development of asthma, nor did it include children with severe asthma or older children.

“The purpose of AsthmaNet is to conduct investigations that refine guidelines for how primary care physicians take care of children and adults with asthma,” Dr. Ross says. “We want to provide evidence that helps primary care doctors recommend the most effective and safest therapies.

“In this case, we were able to address one of the most common questions we get from families of children with asthma. Now we can say with some certainty that parents of young children with mild asthma can feel comfortable reaching for either acetaminophen or ibuprofen and following the manufacturer’s recommendations for dosages without worrying about how it will impact the child’s asthma.”

Contact Dr. Ross at

All National Institutes of Health funding for basic and clinical research is awarded to the School of Medicine at Case Western Reserve University.