Prenatal and infant exposure to the side effects of acetaminophen, the active ingredient in Tylenol and other popular pain medications, may increase the risk of childhood asthma, according to the findings of new research.
In a study published last week in the International Journal of Epidemiology, researchers from Norway and the U.K. report that they have found an association between Tylenol use during pregnancy or shortly after birth, and asthma development during childhood.
The findings appear to back up previous studies linking prenatal Tylenol use and asthma, the researchers said.
The study looked at data involving tens of thousands of children from the Norwegian Mother and Child Cohort and asthma medication dispensing data from the Norwegian Prescription Database. The findings indicated a 13% increased risk when acetaminophen, known as paracetamol in Europe, was used during pregnancy, and a 29% increased risk when infants were given the painkiller. The increases remained after they adjusted for confounding factors.
Researchers found that the prenatal risks were still seen when expecting mothers took the drug for different indications, such as pain, respiratory tract infections, the flu and fever.
“This study provides evidence that prenatal and infant paracetamol exposure have independent associations with asthma development,” the researchers concluded. “Our findings suggest that the associations could not be fully explained by confounding by indication.”
Although most concerns assume Tylenol is safe, acetaminophen products have been linked to a number of potential health risks. The pain killer has been identified as a leading cause for liver injury in the United States, causing an estimated 50,000 emergency room visits each year, including 25,000 hospitalizations and over 450 deaths annually. In addition, use of the medication has been linked to a risk of dangerous skin reactions, like Stephens-Johnson Syndrome.
In recent years, efforts have been ramped up to bring the risk of acetaminophen overdoses to the public’s attention and to reduce the amount of liver injury cases linked to the popular analgesic, which is also found in other pain killers and a number of cold medications.
In 2011, Johnson & Johnson lowered the maximum recommended dosage on Tylenol and other acetaminophen-based products from 4,000 mg per day to 3,000 mg per day. However, the drug maker now faces a number of Tylenol liver failure lawsuits, which involve allegations that important safety information from the public for decades.