Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Asthma Health Center

Font Size

Acetaminophen May Be Linked to Asthma Risk

Study Shows Painkiller Raises Risk of Asthma; Manufacturer Says Drug Is Safe
WebMD Health News
Reviewed by Louise Chang, MD

Nov. 5, 2009 -- The popular pain and fever reliever acetaminophen may be linked with an increased risk of asthma in children and adults, according to a new research review of previously published studies by Canadian researchers.

But the manufacturer of Tylenol -- the brand-name version of acetaminophen -- says the painkiller has a well-established safety record.

Researchers pooled the results of 19 clinical studies, with a total of more than 425,000 participants, to see if the association between the pain reliever use and asthma (and wheezing in children) held up. It did.

What triggered the review? "Concern over the risk of acetaminophen and asthma highlighted by the 2008 ISAAC study, published in The Lancet," says the review's lead author Mahyar Etminan, PharmD, a scientist at the Vancouver Coastal Health Research Institute in British Columbia and an assistant professor of medicine at the University of British Columbia.

In the ISAAC (International Study of Asthma and Allergies in Childhood) study, researchers looked at more than 205,000 children, ages 6 to 7, in 31 countries and found that acetaminophen use for fever in the first year of life was linked to increased risk of asthma symptoms in children 6 to 7 years old. Current use of acetaminophen was also linked to increased risk of asthma symptoms.

Other studies, Etminan says, have produced conflicting results, so the Canadian team conducted the review.

Sales of acetaminophen products in the U.S. are about $1 billion annually, the researchers estimate.

Calculating Asthma Risk

Etminan's team searched the medical literature to find high-quality published studies, trying to quantify the risk of asthma and wheezing among acetaminophen users, as well as the effect of prenatal exposure to the medicine.

After eliminating studies that weren't scientifically sound enough, the researchers focused on 19 studies. Overall, they found that acetaminophen users were 63% more likely to have asthma than nonusers. Other findings:

  • The risk of asthma in children given acetaminophen in the year before their asthma diagnosis was increased by 60%.
  • The risk of asthma in children who used acetaminophen in the first year of life was 47% higher than in those who didn't use it.
  • The risk of asthma in adults who used acetaminophen was 74% higher than in those who did not.
  • Prenatal use of acetaminophen boosted the risk of wheezing by 50% and the risk of asthma by 28% in children.
1 | 2 | 3

When Is Your Asthma Worse?

When Is Your Asthma Worse?

Take the WebMD Asthma assessment to get Personalized Action Plan

Start Now

Today on WebMD

Lung and bronchial tube graphic
5 common triggers.
group jogging in park
Should you avoid fitness activities?
asthma inhaler
Learn about your options.
man feeling faint
What’s the difference?
Madison Wisconsin Capitol
woman wearing cpap mask
red wine pouring into glass
Woman holding inhaler
Man outdoors coughing
Lung and bronchial tube graphic
10 Worst Asthma Cities