The effect of a single dose of acetaminophen on airways response in children with asthma

NSAID Hypersensitivity in the Pediatric Population: Classification and Diagnostic Strategies

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently administered drugs, mainly for their anti-pyretic, but also for pain-relieving and anti-inflammatory effects in children. NSAIDs are composed of structurally divergent subgroups of drugs with similar pharmacological and adverse effects. Aspirin originates from salicin and was the first synthesized analgesic. As a prototype of NSAIDs; aspirin-induced hypersensitivity reactions were first reported, but subsequently, other phenotypes of hypersensitivity reactions were also described with aspirin and other NSAIDs. There are certain challenging aspects of NSAID-hypersensitivity in the pediatric population that need to be further investigated. These include the effect of age on drug metabolism and the natural history of the various phenotypes of NSAID-hypersensitivity, the effect of certain co-factors (infections, exercise) on NSAID-hypersensitivity, and diagnostic clinical and laboratory biomarkers clarifying the endotypes. In recent years, a non-negligible number of case series, studies and expert panel reports have been published in this field with some novel features and diagnostic modalities in the pediatric population. With the current review; the clinical phenotypes and diagnostic and management modalities of suspected NSAID-induced hypersensitivity reactions in childhood and adolescence were explained and updated by examining past and current publications.

Adherence rates during a randomized controlled trial evaluating the use of blinded acetaminophen and ibuprofen in children with asthma

BACKGROUND/AIMS

When conducting clinical trials comparing over-the-counter (OTC) medications, the wide availability of these treatments are a potential challenge to maintaining study integrity. We seek to describe adherence to a study protocol involving widely available OTC medications.

METHODS

To prospectively evaluate associations between acetaminophen use and asthma in 300 children aged 1-5 years, we conducted a double blind, randomized, controlled trial where parents administered blinded forms of either acetaminophen or ibuprofen as needed to their children over a 48 week period. Written and verbal instructions encouraged the exclusive use of the blinded study medication and discouraged OTC use. Adherence was determined by evaluating the frequency of use of per-protocol blinded study medication compared to off-protocol use of OTC medications.

RESULTS

4195 doses of acetaminophen or ibuprofen were received by children during the study which included 3664 doses (87.3%) of blinded study medication adhering to the protocol and 531 doses (12.7%) of OTC products deviating from the protocol with better adherence among those randomized to ibuprofen as compared to acetaminophen (89.5% vs. 85.5% of doses, p < 0.01). Individually, 227 participants (75.7%) remained fully adherent by not receiving any OTC medications. Pre-study preference for either acetaminophen or ibuprofen by the participants' families was not associated with differential rates of adherence to the blinded medication.

CONCLUSION

This parallel study demonstrated greater than 85% of acetaminophen or ibuprofen doses were blinded study medications adhering to the protocol while less than 15% were OTC deviations from the protocol. This successfully implemented study design provides a template to comparatively evaluate these and other OTC medications.

Risk of acute exacerbation between acetaminophen and ibuprofen in children with asthma

Background

Antipyretics are widely prescribed in pediatric practice. Some reports have mentioned that acetaminophen and non-steroid anti-inflammatory drugs may negatively affect asthma control by causing asthma exacerbation (AE). However, many confounding factors can also influence the risks. We assessed the impact of using acetaminophen or ibuprofen on AE in asthmatic children, especially those with strong risk factors.

Methods

We used the 2010 Taiwan National Health Insurance Research Database and identified 983 children with persistent asthma aged 1-5 years old; among them, 591 used acetaminophen alone and 392 used ibuprofen alone in 2010. Then, we analyzed the risk of AE over 52 weeks in the patients with and without severe AE in the previous year.

Results

The ibuprofen group had a higher risk of an emergency room (ER) visit or hospitalization for AE (odds ratio (OR) = 2.10, 95% confidence interval (CI) [1.17-3.76], P = 0.01). Among asthmatic children who had severe AE in the previous year, the risk of AE was higher in the ibuprofen group than in the acetaminophen group (OR = 3.28, 95% CI [1.30-8.29], P = 0.01), where as among those who did not, the risks of AE were similar between the acetaminophen and ibuprofen groups (OR = 1.52, 95% CI [0.71-3.25], P = 0.28).

Conclusions

Among young asthmatic children, use of ibuprofen was associated with a higher risk of AE than acetaminophen, if they had severe AE with ER visit or hospitalization in the previous year. Pediatricians should use antipyretics among children with asthma after a full evaluation of the risk.

Acetaminophen is both bronchodilatory and bronchoprotective in human precision cut lung slice airways

Epidemiologic studies have demonstrated an association between acetaminophen (APAP) use and the development of asthma symptoms. However, few studies have examined relationships between APAP-induced signaling pathways associated with the development of asthma symptoms. We tested the hypothesis that acute APAP exposure causes airway hyper-responsiveness (AHR) in human airways. Precision cut lung slice (PCLS) airways from humans and mice were used to determine the effects of APAP on airway bronchoconstriction and bronchodilation and to assess APAP metabolism in lungs. APAP did not promote AHR in normal or asthmatic human airways ex vivo. Rather, high concentrations mildly bronchodilated airways pre-constricted with carbachol (CCh), histamine (His), or immunoglobulin E (IgE) cross-linking. Further, the addition of APAP prior to bronchoconstrictors protected the airways from constriction. Similarly, in vivo treatment of mice with APAP (200 mg/kg IP) resulted in reduced bronchoconstrictor responses in PCLS airways ex vivo. Finally, in both mouse and human PCLS airways, exposure to APAP generated only low amounts of APAP-protein adducts, indicating minimal drug metabolic activity in the tissues. These findings indicate that acute exposure to APAP does not initiate AHR, that high-dose APAP is protective against bronchoconstriction, and that APAP is a mild bronchodilator.

2016 Update of the Italian Pediatric Society Guidelines for Management of Fever in Children

OBJECTIVE

To review new scientific evidence to update the Italian guidelines for managing fever in children as drafted by the panel of the Italian Pediatric Society.

STUDY DESIGN

Relevant publications in English and Italian were identified through search of MEDLINE and the Cochrane Database of Systematic Reviews from May 2012 to November 2015.

RESULTS

Previous recommendations are substantially reaffirmed. Antipyretics should be administered with the purpose to control the child's discomfort. Antipyretics should be administered orally; rectal administration is discouraged except in the setting of vomiting. Combined use of paracetamol and ibuprofen is discouraged, considering risk and benefit. Antipyretics are not recommended preemptively to reduce the incidence of fever and local reactions in children undergoing vaccination, or in attempt to prevent febrile convulsions in children. Ibuprofen and paracetamol are not contraindicated in children who are febrile with asthma, with the exception of known cases of paracetamol- or nonsteroidal anti-inflammatory drug-induced asthma.

CONCLUSIONS

Recent medical literature leads to reaffirmation of previous recommendations for use of antipyretics in children who are febrile.

The association between paracetamol and asthma is still under debate

OBJECTIVE

To analyse the relationship between paracetamol and asthma.

DATA SOURCES

An English literature search using electronic search engines (PubMed and EMBASE) was conducted.

STUDY SELECTIONS

Articles published in peer-review journals, from 1990 to December 2015 were included. To perform the search for the most suitable and representative articles, keywords were selected ("asthma," "paracetamol" and "acetaminophen"). The evidence level was rated according to the criteria of the Oxford Centre For Evidence-Based Medicine.

RESULTS

The exposure to paracetamol during pregnancy was analysed in several cohort studies, showing an association between the prenatal exposure to paracetamol with suffering from asthma or presence of wheezing in childhood, especially for persistent wheezing. Nevertheless, a recent study concluded that the relationship between asthma and paracetamol is explained, at least in part, by confounding factors. Several works have also associated the exposure to paracetamol in the first years of life or in adults with the development of childhood asthma. Several pathophysiological mechanisms are known that could explain this relationship, such as the glutathione pathway, the decrease in the release of Th1 cytokines that are normally produced during febrile episodes, which would then lead to a predominance of Th2 cytokines, the cytotoxic effect of paracetamol for pneumocytes, a modulator effect on the activity of myeloperoxidase, as well as the possible antigenic effect of paracetamol, mediated by IgE.

CONCLUSIONS

There are many arguments that suggest a relationship between the use of paracetamol with the appearance of asthmatic symptoms, however the evidence is inconclusive.

Acetaminophen versus Ibuprofen in Young Children with Mild Persistent Asthma

BACKGROUND

Studies have suggested an association between frequent acetaminophen use and asthma-related complications among children, leading some physicians to recommend that acetaminophen be avoided in children with asthma; however, appropriately designed trials evaluating this association in children are lacking.

METHODS

In a multicenter, prospective, randomized, double-blind, parallel-group trial, we enrolled 300 children (age range, 12 to 59 months) with mild persistent asthma and assigned them to receive either acetaminophen or ibuprofen when needed for the alleviation of fever or pain over the course of 48 weeks. The primary outcome was the number of asthma exacerbations that led to treatment with systemic glucocorticoids. Children in both groups received standardized asthma-controller therapies that were used in a simultaneous, factorially linked trial.

RESULTS

Participants received a median of 5.5 doses (interquartile range, 1.0 to 15.0) of trial medication; there was no significant between-group difference in the median number of doses received (P=0.47). The number of asthma exacerbations did not differ significantly between the two groups, with a mean of 0.81 per participant with acetaminophen and 0.87 per participant with ibuprofen over 46 weeks of follow-up (relative rate of asthma exacerbations in the acetaminophen group vs. the ibuprofen group, 0.94; 95% confidence interval, 0.69 to 1.28; P=0.67). In the acetaminophen group, 49% of participants had at least one asthma exacerbation and 21% had at least two, as compared with 47% and 24%, respectively, in the ibuprofen group. Similarly, no significant differences were detected between acetaminophen and ibuprofen with respect to the percentage of asthma-control days (85.8% and 86.8%, respectively; P=0.50), use of an albuterol rescue inhaler (2.8 and 3.0 inhalations per week, respectively; P=0.69), unscheduled health care utilization for asthma (0.75 and 0.76 episodes per participant, respectively; P=0.94), or adverse events.

CONCLUSIONS

Among young children with mild persistent asthma, as-needed use of acetaminophen was not shown to be associated with a higher incidence of asthma exacerbations or worse asthma control than was as-needed use of ibuprofen. (Funded by the National Institutes of Health; AVICA ClinicalTrials.gov number, NCT01606319.).

The association between paracetamol use and asthma: causation or coincidence?

A better understanding of the causation of asthma and allergic disorders could potentially lead to intervention strategies that reduce their prevalence and severity. One potential causative factor is the use of paracetamol. Most of the evidence for the link with asthma is from non-experimental studies of paracetamol exposure in utero, infancy, childhood and adult life; however, it has been difficult to rule out confounding and bias in the associations observed. The two randomized clinical trials of the effect of paracetamol in patients with asthma have been difficult to interpret, due to methodological issues. There have been no randomized controlled trials of paracetamol use and the development of asthma. Both asthma and paracetamol use are common, and so even if there is a relatively small effect of paracetamol exposure on the development of asthma or its severity, then such an effect would be of major public health significance. It is proposed that randomized controlled trials of the effect of paracetamol on the development of asthma and its severity are a high research priority.

Prenatal acetaminophen induces liver toxicity in dams, reduces fetal liver stem cells, and increases airway inflammation in adult offspring

BACKGROUND & AIMS

During pregnancy, acetaminophen is one of the very few medications recommended by physicians to treat fever or pain. Recent insights from epidemiological studies suggest an association between prenatal acetaminophen medication and an increased risk for development of asthma in children later in life. The underlying pathogenesis of such association is still unknown.

METHODS

We aimed to develop a mouse model to provide insights into the effect of prenatal acetaminophen on maternal, fetal and adult offspring's health. The toxic effect of acetaminophen was studied in mice on 1) maternal liver; mirrored by biomarkers of liver injury, centrilobular necrosis, and infiltration of granulocytes; 2) fetal liver; reflected by the frequency of hematopoietic stem cells, and 3) postnatal health; evaluated by the severity of allergic airway inflammation among offspring.

RESULTS

We observed an increased susceptibility towards acetaminophen-induced liver damage in pregnant mice compared to virgins. Moreover, hematopoietic stem cell frequency in fetal liver declined in response to acetaminophen. Furthermore, a greater severity of airway inflammation was observed in offspring of dams upon prenatal acetaminophen treatment, identified lung infiltration by leukocytes and eosinophil infiltration into the airways.

CONCLUSION

Our newly developed mouse model on prenatal use of acetaminophen reflects findings from epidemiological studies in humans. The availability of this model will allow improvement in our understanding of how acetaminophen-related hepatotoxicity is operational in pregnant individuals and how an increased risk for allergic diseases in response to prenatal acetaminophen is mediated. Such insights, once available, may change the recommendations for prenatal acetaminophen use.

Paracetamol exposure in pregnancy and early childhood and development of childhood asthma: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

While paracetamol exposure in pregnancy and early infancy has been associated with asthma, it remains unclear whether this is confounded by respiratory tract infections, which have been suggested as an alternative explanation. We undertook a systematic review and meta-analysis of longitudinal studies that reported the association between paracetamol exposure during pregnancy or infancy and the subsequent development of childhood asthma (≥5 years).

METHODS

Two independent researchers searched the databases EMBASE and PUBMED on 12 August 2013 for relevant articles using predefined inclusion and exclusion criteria. Study quality was assessed and results were pooled using fixed effect models or random effect models when moderate between-study heterogeneity was observed. We explicitly assessed whether the observed associations are due to confounding by respiratory tract infections.

RESULTS

Eleven observational cohort studies met the inclusion criteria. Any paracetamol use during the first trimester was related to increased risk of childhood asthma (5 studies, pooled OR=1.39, 95% CI 1.01 to 1.91) but there was marked between-study heterogeneity (I(2)=63%) and only one of these studies adjusted for maternal respiratory tract infections. Increasing frequency of use of paracetamol during infancy was associated with increased odds of childhood asthma (3 studies, pooled OR=1.15, 95% CI 1.00 to 1.31 per doubling of days exposure), but in these same three studies adjusting for respiratory tract infections reduced this association (OR=1.06, 95% CI 0.92 to 1.22).

DISCUSSION

The association during early pregnancy exposure was highly variable between studies and exposure during infancy appears to be moderately confounded by respiratory tract infections. There is insufficient evidence to warrant changing guidelines on early life paracetamol exposure at this time.

The association between acetaminophen and asthma: should its pediatric use be banned?

During the last few decades, a huge epidemiological effort has been made all over the world in order to cast some light on the origin of asthma (or 'wheezing disorders' as a general term) and its recent increase in prevalence. The focus on genetic factors has failed to show any genetic signal strong enough to be seriously considered, and the tiny genetic signals found have never been appropriately replicated. The focus on environmental factors has provided some variable signals on the role of infections, allergens and bacterial substances, the direction of which have curiously varied from protecting to inducing asthma. The only environmental factor that has launched a large and consistent epidemiological signal, found in almost every epidemiological study addressing the issue, is previous acetaminophen exposure, which consistently increases the prevalence and clinical manifestations of every wheezing disorder under study. Is acetaminophen a real asthma promoter or an innocent bystander?