MONDAY, Nov. 7, 2011 (HealthDay News) -- Taken in the proper dose, acetaminophen has long been considered one of the safest over-the-counter medications. It's approved for use in children, and many obstetricians are even OK with its use during pregnancy.
But an Ohio pediatrician thinks it's time to rein in use of acetaminophen -- more popularly known as Tylenol -- particularly in people with asthma.
"The fundamental issue is that there's an epidemiological problem associated with acetaminophen and asthma," explained Dr. John McBride, vice chair of the department of pediatrics and director of the Robert T. Stone Respiratory Center at Akron Children's Hospital.
"Is that because acetaminophen contributes to asthma, or is it just because people with asthma tend to take acetaminophen?" he said.
Until a large-scale study definitively answers that question, McBride said, "I think we owe it to our patients and their parents to make it clear that maybe acetaminophen is bad. And, if there are alternatives, people might want to use those alternatives until they know acetaminophen is safe."
McBride reviewed the available evidence linking the pain reliever/fever reducer and asthma for an article published in the December issue of Pediatrics.
One source was the International Study of Allergy and Asthma in Childhood, which included more than half a million children at 122 centers in 54 countries. About 200,000 kids were 6 to 7 years old, and 320,000 were between 13 and 14 years old.
Almost one in three of the older children reported taking acetaminophen at least once a month.
In children who took acetaminophen more than once a year, but less than once a month, the researcher found the risk of current asthma was 61 percent higher in the 6 to 7 year olds. For these young children who took acetaminophen more than once a month, the risk of having asthma was more than tripled.
The older children fared slightly better with an increased risk of 43 percent in those who took the drug more than once a year, but less than once a month. For those who took acetaminophen more than once a month, the risk of having asthma increased by 2.5 times, according to the report.
McBride calculated that if acetaminophen exposure was eliminated in that teen group, the rate of severe asthma symptoms would decline by 43 percent.
He also reviewed a meta-analysis of six studies involving almost 90,000 adults in total. Weekly use of acetaminophen was linked to a 1.74 times higher risk of asthma in adults, McBride found.
In addition, the researcher looked at two prospective studies done on acetaminophen and asthma in the early 1990s. These studies, which followed a group of individuals for a period of time, also found a strong link between asthma and acetaminophen.
McBride said the evidence is stronger that acetaminophen exacerbates current asthma, but that there's also evidence that it may be a cause of asthma, too.
How this occurs remains subject to debate, but some researchers believe acetaminophen increases airway inflammation in people with asthma or a predisposition to the breathing disorder, he said.
Dr. Len Horovitz, an internist and pulmonary specialist at Lenox Hill Hospital in New York City, said, "This information suggests that we have to be cautious about acetaminophen in children with asthma or a family history of asthma. The alternative is ibuprofen, which a lot of parents seem to prefer anyway."
"I do think further research is needed," Horovitz added.
He cautioned that a small group of people with asthma are sensitive to aspirin, and said there are some others who have nasal polyps who shouldn't take ibuprofen (Advil, Motrin).
Not everyone is convinced that the association seen in the new study leads to cause and effect.
"Asthma is such a complex disease, and people all over the world are trying to figure out what causes it," said Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital and Medical Center in Detroit. She said that the asthma likely has a number of causes, not just one.
"I don't feel strongly swayed enough to tell my patients they shouldn't take acetaminophen. In anyone with a fever, it's good to minimize the amount of medications and give them just when they're needed." But, she said, an untreated fever can also be dangerous, and parents want to make their children comfortable when they're sick.
But until there's good evidence that acetaminophen is safe, McBride is telling his patients to avoid it.
If his own wife were pregnant, he said he'd suggest that she avoid taking acetaminophen, too. "It's not because I think it's very likely that it's a problem in pregnancy, but in the absence of evidence, why take it?" said McBride.
Learn more about asthma triggers and treatment from the American Academy of Allergy, Asthma and Immunology.