Can acetaminophen cause asthma?
© 2013 Roy Benaroch, MD
Tylenol (acetaminophen) replaced aspirin as everyone’s favorite pain reliever-fever reducer in the 1980’s, when aspirin was linked to a rare fatal liver disorder called Reye’s Syndrome. Acetaminophen is very widely used now, even in newborns, and is considered safe as, well, something very safe. Except maybe it isn’t.
Some evidence is adding up that acetaminophen could be linked to the rising rates of asthma in the developed world. There’s a certain biologic plausibility to it—acetaminophen depletes the body of glutathione, which may prevent that molecule from stopping inflammation in the lungs. And several epidemiologic studies, and at least one randomized trial from 2002, have seemed to confirm the link. The positive evidence for the association was summed up in this New York Times article from 2011.
However, a more recent NYT article, this one from last week, refutes the claim. The article quotes the author of an as-yet-unpublished study who says that it’s not the medications like acetaminophen that increase asthma risk, but common upper respiratory infections—which are often treated with Tylenol. If this author is correct, the acetaminophen is going along for the ride, but isn’t itself causing the asthma.
That’s science for you. A whole lot of studies, and we’re still not sure.
What I am sure of is this: all medicines, if they’re biologically active at all, have side effects. There is just no way around that. If someone is trying to sell you a perfectly-safe “medicine”, it isn’t a medicine. It’s a placebo.
No medicine ought to be taken unless it’s needed, and when doctors and patients think about the risks and benefits of any medication, we ought to figure in at least a little fudge factor for possible risks we don’t even know about yet.
Related posts:
Acetaminophen safety alert (2009)
Explore posts in the same categories: In the newsTags: Asthma, fever, RAD, tylenol
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The Pediatric Insider 
May 31, 2013 at 9:01 am
First of all, Dr. Benaroch deserves much praise for his blog and the excellent and timely information it provides. As a pediatric pulmonologist at Georgia Pediatric Pulmonology Associates, PC, I practice in the same community as Dr. Roy and have enjoyed working with him in the management of mutual patients.
The issue of Acetaminophen and Asthma continues to be topical but is, in my opinion, a prime example of faulty science. While there is biologic plausibility, the apparent association of the rise in asthma prevalence and the transition from ASA to acetaminophen as the antipyretic of choice does not imply causality.
I recently debated my esteemed pulmonology colleague, Dr. John McBride on this issue at the ACCP/AAP Celebration of Pediatric Pulmonology course in April. I found that the argument of causation is flawed by two types of bias-Confounding by Indication and Confounding by Reverse Causation.
In the spirit of strait talk that characterizes Dr. Benaroch’s blog, these examples of bias evolve from the fact that the conditions for which acetaminophen is most often used (fever associated with intercurrent viral URIs in young children) are also the most common causes of a clinical exacerbation of asthma in young children. Additionally, there is evidence that early viral infection (particularly due to Rhinovirus) may play a role in the onset of asthma in children at risk (family history, eczema, allergic rhinitis..etc).
At a time when we should be focused on the appropriate diagnosis and management of asthma in young children (asthma is the #1 single diagnosis to result in admission to the ED or inpatient service of every children’s hospital in the US), this issue leads to cognitive dissonance (confusion) that distracts us from managing the asthma problem with patient/family education and sound medical management.
Also, consider that Reye’s Syndrome is the only disease to essentially disappear in my 34 years of practice coincident with the switch to acetaminophen as the anti-pyretic of choice.
I am also married to an excellent general pediatrician who thinks we so called smart sub-specialists should stick to our main focus and not suggest that primary care docs get into long winded discussion with parents about antipyretics..particularly if the science is more than a bit flawed.
10 years ago, i developed a not for profit, Not One More Life, Inc (NOML) http://www.notonemorelife.org NOML is dedicated to reducing the burden of asthma and other lung diseases among groups that experience disparate morbidity and mortality attributable to these conditions. These include minorities, children, women and the poor.
NOML’s website offers up to 8 hours of fully accredited free on line CME focused on asthma and related issues.
LeRoy M. Graham MD, FCCP
Georgia Pediatric Pulmonology Associates, PC
Not One More Life, Inc. http://www.notonemorelife.org
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May 31, 2013 at 8:59 pm
Thank you Dr. Graham! I’m really honored– and honestly, very happy– that you come by and added your comment.
Dr. Graham, summing up my opinion of him and his group: The man knows his stuff. If he’s not convinced that acetaminophen is a significant worry, that should be a big reassurance for parents (and pediatricians!).
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