The Association Between Acetaminophen and Asthma

Should Its Pediatric Use Be Banned?

Antonio Martinez-Gimeno; Luis García-Marcos

Disclosures

Expert Rev Resp Med. 2013;7(2):113-122. 

In This Article

The Question of Acetaminophen & Wheezing Disorders in the Light of Evidence-based Medicine

To properly address the question of acetaminophen and wheezing disorders in the light of evidence-based medicine, one must analyze the different statements pertaining at different levels of knowledge that we have already discussed which, although related, do not need the same sort of supporting evidence.

The authors can classify these statements in epidemiological statements and clinical intervention statements. While the former have a large body of evidence in their support, the latter are less well supported.

The first epidemiological statement, acetaminophen exposure is associated with an increase in wheezing disorders prevalence, can be ranked in the top level of evidence-based medicine grading systems, being supported by a good number of well-designed, large epidemiological studies of every nature and confirmed by well-designed systematic reviews and meta-analyses. This statement is valid for in utero, childhood and adult life exposure. The only drawback of this body of evidence is the possibility of a huge source of bias confounding the whole association, as already discussed.

The second epidemiological statement, acetaminophen exposure is associated with an increase in asthma morbidity, can also be ranked in the top level of evidence-based medicine grading systems, being also supported by a good number of well-designed large epidemiological studies and confirmed by well-designed systematic reviews and meta-analyses. Importantly, this statement is also supported by a randomized double-blind clinical trial in children, which shows that avoiding acetaminophen in febrile conditions reduces asthma outpatient visits in the following month, as already discussed.[15] So, it must be ranked in the top level of evidence-based medicine grading systems.

The clinical intervention statements derive from the epidemiological statements and seem quite logical. However, clinical and physiopathological reasoning is the humblest level of evidence and has proved to be unreliable in many clinical situations. Therefore, these clinical intervention statements must be directly and carefully studied.

The first clinical intervention statement can be analyzed as follows: avoiding acetaminophen exposure (intervention) in pregnant women, children and adults (object population) reduces wheezing disorders prevalence (clinical outcome). This statement has never been directly studied by means of a clinical trial, as previously discussed. Therefore, it must be ranked low in the evidence-based medicine grading systems. Its supporting evidence comes from clinical and epidemiological reasoning and experts' opinion. It is clearly a statement, which deserves further appropriate studies.

The second clinical intervention statement is: avoiding (or limiting) acetaminophen exposure (intervention) in asthmatic children and adults (object population) reduces asthma morbidity (clinical outcome). This statement is supported, in children, by the well-designed, large randomized clinical trial already discussed.[15] Therefore, it can be ranked highly, but not top, in evidence-based medicine grading systems.

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