Prophylactic management of children at risk for recurrent upper respiratory infections: the Preventia I Study

Newer-generation antihistamines and the risk of adverse events in children: A systematic review

BACKGROUND

H1-antihistamines (AHs) are widely used for the treatment of allergic diseases, being one of the most commonly prescribed classes of medications in pediatrics. Newer-generation AHs are associated with fewer adverse effects compared with first-generation AHs. However, their relative harms in the pediatric population still need scrutiny.

METHODS

We performed a systematic review of randomized controlled trials (RCTs), which included comparisons of safety parameters between an orally administered newer-generation AH and another AH (first- or second-generation), montelukast, or placebo in children aged ≤12 years. We searched MEDLINE and CENTRAL, independently extracted data on study population, interventions, adverse events (AEs), and treatment discontinuations, and assessed the methodologic quality of the included RCTs using the Cochrane's risk of bias tool.

RESULTS

Forty-five RCTs published between 1989 and 2017 met eligibility criteria. The majority of RCTs included school-aged children with allergic rhinitis and had a follow-up period of up to a month. Four RCTs reported serious AEs in patients receiving a newer-generation AH, but only two patients experienced a possibly drug-related serious AE. The occurrence of AEs, drug-related AEs, and treatment discontinuations due to AEs varied between RCTs. Most AEs reported were of mild intensity. Indirect evidence indicates that cetirizine is more sedating than the other newer-generation AHs.

CONCLUSION

Our findings confirm that newer-generation AHs have a favorable safety and tolerability profile. However, we could not draw firm conclusions regarding the comparative safety profile of the newer-generation AHs due to the paucity of head-to-head RCTs, variation in definitions and reporting of AEs, and short follow-up duration.

Histamine, histamine receptors, and anti-histamines in the context of allergic responses

Histamine is a bioactive amine which is considered a key player in the allergic response. Thus, histamine receptor blockers (antihistamines) play an important role in the treatment of a number atopic diseases such as allergic rhinitis, conjunctivitis, and acute and chronic forms of urticaria. Histamine is produced by immune cells but also by bacteria in the gut. Beyond its role in the acute allergic response, histamine exerts numerous effects by binding to its 4 pleiotropic G-protein coupled histamine receptors. Here, we describe the roles of these histamine receptors and antihistamines in the human system, clinical applications, side effects, and novel concepts for the usage of antihistamines with different specificity based on guidelines and recommendations.

Statement of novelty: This review provides an overview of histamine receptors and links it to clinical relevance of antagonizing their action in clinical routine.

Safety and tolerability of bilastine 10 mg administered for 12 weeks in children with allergic diseases

BACKGROUND

Regulations on medicinal products for paediatric use require that pharmacokinetics and safety be characterized specifically in the paediatric population. A previous study established that a 10-mg dose of bilastine in children aged 2 to <12 years provided an equivalent systemic exposure as 20 mg in adults. The current study assessed the safety and tolerability of bilastine 10 mg in children with allergic rhinoconjunctivitis and chronic urticaria.

METHODS

In this phase III, multicentre, double-blind study, children were randomized to once-daily treatment with bilastine 10-mg oral dispersible table (n = 260) or placebo (n = 249) for 12 weeks. Safety evaluations included treatment-emergent adverse events (TEAEs), laboratory tests, cardiac safety (ECG recordings) and somnolence/sedation using the Pediatric Sleep Questionnaire (PSQ).

RESULTS

The primary hypothesis of non-inferiority between bilastine 10 mg and placebo was demonstrated on the basis of a near-equivalent proportion of children in each treatment arm without TEAEs during 12 weeks' treatment (31.5 vs. 32.5%). No clinically relevant differences between bilastine 10 mg and placebo were observed from baseline to study end for TEAEs or related TEAEs, ECG parameters and PSQ scores. The majority of TEAEs were mild or moderate in intensity. TEAEs led to discontinuation of two patients treated with bilastine 10 mg and one patient treated with placebo.

CONCLUSIONS

Bilastine 10 mg had a safety and tolerability profile similar to that of placebo in children aged 2 to <12 years with allergic rhinoconjunctivitis or chronic urticaria.

Off-label prescribing for allergic diseases in children

The majority of drugs prescribed have not been tested in children and safety and efficacy of children's medicines are frequently supported by low quality of evidence. Therefore, a large percentage of prescriptions for children in the clinical daily practice are used off label. Despite the several recent legislation and regulatory efforts performed worldwide, they have not been successful in increasing availability of medicines adapted to children. Moreover, if we consider that 30% of the prescribed drugs for children are for the respiratory field and only 4% of new investigation projects for children research were proposed to access drugs for respiratory and allergy treatment, there is a clear imbalance of the children needs in this therapeutic area. This narrative review aimed to describe and discuss the off-label use of medicines in the treatment and control of respiratory and allergic diseases in children. It was recognized that a large percentage of prescriptions performed for allergy treatment in daily clinical practice are off label. The clinicians struggle on a daily basis with the responsibility to balance risk-benefits of an off-label prescription while involving the patients and their families in this decision. It is crucial to increase awareness of this reality not only for the clinician, but also to the global organizations and competent authorities. New measures for surveillance of off-label use should be established, namely through population databases implementation. There is a need for new proposal to correct the inconsistency between the priorities for pediatric drug research, frequently dependent on commercial motivations, in order to comply to the true needs of the children, especially on the respiratory and allergy fields.

Safety considerations in the management of allergic diseases: focus on antihistamines

OBJECTIVE

To conduct a systematic review of evidence supporting the safety profiles of frequently used oral H(1)-antihistamines (AHs) for the treatment of patients with histamine-release related allergic diseases, e.g. allergic rhinitis and urticaria, and to compare them to the safety profiles of other medications, mostly topical corticosteroids and leukotriene antagonists (LTRA).

RESEARCH DESIGN AND METHODS

Systematic search of the published literature (PubMed) and of the regulatory authorities databases (EMA and FDA) for oral AHs.

RESULTS

Similarly to histamine, antihistamines (AHs) have organ-specific efficacy and adverse effects. The peripheral H(1)-receptor (PrH1R) stimulation leads to allergic symptoms while the brain H(1)-receptor (BrH1R) blockade leads to somnolence, fatigue, increased appetite, decreased cognitive functions (impaired memory and learning), seizures, aggressive behaviour, etc. First-generation oral AHs (FGAHs) inhibit the effects of histamine not only peripherally but also in the brain, and additionally have potent antimuscarinic, anti-α-adrenergic and antiserotonin effects leading to symptoms such as visual disturbances (mydriasis, photophobia, and diplopia), dry mouth, tachycardia, constipation, urinary retention, agitation, and confusion. The somnolence caused by FGAHs interferes with the natural circadian sleep-wake cycle and therefore FGAHs are not suitable to be used as sleeping pills. Second-generation oral AHs (SGAHs) have proven better safety and tolerability profiles, much lower proportional impairment ratios, with at least similar if not better efficacy, than their predecessors. Only SGAHs, and especially those with a proven long-term (e.g., ≥12 months) clinical safety, should be prescribed for young children. Evidence exist that intranasally applied medications, like intranasal antihistamines, have the potential to reach the brain and cause somnolence.

CONCLUSIONS

Second-generation oral antihistamines are the preferred first-line treatment option for allergic rhinitis and urticaria. Patients taking SGAHs report relatively little and mild adverse events even after long-term continuous treatments. An antihistamine should ideally possess high selectivity for the H(1)-receptor, high PrH1R occupancy and low to no BrH1R occupancy.

[Secondary and tertiary prevention of allergic asthma in children]

Asthma is a disease of the lung epithelial barrier, most often associated with allergy in children. Asthma and allergy are two distinct diseases, but the phenotypic expression of asthma depends on atopic status. A better definition of phenotypes of asthma would result in better targeting of prevention and treatment modalities. Secondary prevention aims to prevent the onset of asthma and the acquisition of new sensitizations in sensitized children. Studies concerning allergen avoidance are insufficient to reach a definitive conclusion and antihistamines have not been shown to be effective. The results for specific immunotherapy suggest a benefit to prevent transition from allergic rhinitis to asthma and the onset of new sensitizations. Tertiary prevention aims to reduce symptoms in children with an existing allergic asthma diagnosis. The avoidance of known respiratory allergens will only be effective in combination with management of the whole environment. Specific immunotherapy has a real place, in combination with background therapy. It should be used according to guidelines in appropriately treated patients.

Risk of first-generation H(1)-antihistamines: a GA(2)LEN position paper

BACKGROUND

First-generation H(1)-antihistamines obtained without prescription are the most frequent form of self-medication for allergic diseases, coughs and colds and insomnia even though they have potentially dangerous unwanted effects which are not recognized by the general public.

AIMS

To increase consumer protection by bringing to the attention of regulatory authorities, physicians and the general public the potential dangers of the indiscriminate use first-generation H(1)-antihistamines purchased over-the counter in the absence of appropriate medical supervision.

METHODS

A GA(2)LEN (Global Allergy and Asthma European Network) task force assessed the unwanted side-effects and potential dangers of first-generation H1-antihistamines by reviewing the literature (Medline and Embase) and performing a media audit of US coverage from 1996 to 2008 of accidents and fatal adverse events in which these drugs were implicated.

RESULTS

First-generation H(1)-antihistamines, all of which are sedating, are generally regarded as safe by laypersons and healthcare professionals because of their long-standing use. However, they reduce rapid eye movement (REM)-sleep, impair learning and reduce work efficiency. They are implicated in civil aviation, motor vehicle and boating accidents, deaths as a result of accidental or intentional overdosing in infants and young children and suicide in teenagers and adults. Some exhibit cardiotoxicity in overdose.

CONCLUSIONS

This review raises the issue of better consumer protection by recommending that older first-generation H(1)-antihistamines should no longer be available over-the-counter as prescription- free drugs for self-medication of allergic and other diseases now that newer second- generation nonsedating H(1)-antihistamines with superior risk/benefit ratios are widely available at competitive prices.

Levocetirizine in the treatment of allergic diseases

BACKGROUND

Levocetirizine, the R-enantiomer of cetirizine dihydrochloride, is a new molecule with a potent and selective antihistamine activity.

OBJECTIVE

To investigate the evidence that levocetirizine is an effective therapy for allergic disease.

METHODS

Evaluation of published articles in English, or having an English abstract.

RESULTS

Clinical trials indicate that levocetirizine is safe and effective for the treatment of allergic rhinitis and chronic idiopathic urticaria. The compound shows a rapid onset of action, high bioavailability and affinity for the H1 receptor. Moreover, this molecule demonstrates many anti-inflammatory effects that enhance the clinical therapeutic benefit not only in short-term but also in long-term treatments, as reported in recent trials utilizing levocetirizine for several months.

CONCLUSION

Levocetirizine confirms its safe effective activity for treatment of allergic disease in both adults and children.

H1 antihistamines: current status and future directions

In this review, we compare and contrast the clinical pharmacology, efficacy, and safety of first-generation H1 antihistamines and second-generation H1 antihistamines. First-generation H1 antihistamines cross the blood-brain barrier, and in usual doses, they potentially cause sedation and impair cognitive function and psychomotor performance. These medications, some of which have been in use for more than 6 decades, have never been optimally investigated. Second-generation H1 antihistamines such as cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine cross the blood-brain barrier to a significantly smaller extent than their predecessors. The clinical pharmacology, efficacy, and safety of these medications have been extensively studied. They are therefore the H1 antihistamines of choice in the treatment of allergic rhinitis, allergic conjunctivitis, and urticaria. In the future, clinically advantageous H1 antihistamines developed with the aid of molecular techniques might be available.

Anti-histamines for prolonged non-specific cough in children

BACKGROUND

Non-specific cough is defined as non-productive cough in the absence of identifiable respiratory disease or known aetiology. It is commonly seen in paediatric practice. These children are treated with a variety of therapies including anti-histamines. Also, anti-histamines are advocated as an empirical treatment in adults with chronic cough.

OBJECTIVES

To evaluate the effectiveness of anti-histamines in treating children with prolonged non-specific cough.

SEARCH STRATEGY

We searched the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, OLDMEDLINE and EMBASE databases. The latest searches were performed in November 2007.

SELECTION CRITERIA

All randomised controlled trials comparing anti-histamines with a placebo or placebo-like medication with cough as an outcome, where cough is not primarily related to an underlying respiratory disorder such as cystic fibrosis, asthma, or suppurative lung disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data.

MAIN RESULTS

Three included therapeutic studies had 182 randomised participants with 162 completing the trials although in one study, children with recurrent wheeze were also included. The two included safety evaluation studies randomised 963 participants with 793 completing the trials. Clinical heterogeneity was evident and limited data prevented combining data for meta-analysis. The two larger therapeutic studies described significant improvement in both the intervention and the placebo/placebo-like arms with no significant difference between the two groups. In the study with the smallest sample size, cetirizine (a second generation anti-histamine) was significantly more efficacious than placebo in reducing chronic cough in children associated with seasonal allergic rhinitis, and the effect was seen within two weeks of therapy. Combined data from the safety evaluation studies revealed a non-significant difference between groups (OR 1.6, 95% CI 0.7 to 3.82) for cough as an adverse event but the trend favoured the placebo arm.

AUTHORS' CONCLUSIONS

This review has significant limitations. However, our finding of uncertain efficacy of anti-histamines for chronic cough are similar to that for acute cough in children. In contrast to recommendations in adults with chronic cough, anti-histamines cannot be recommended as empirical therapy for children with chronic cough. If anti-histamines were to be trialled in these children, current data suggest a clinical response (time to response) occurs within two weeks of therapy. However the use of anti-histamines in children with non-specific cough has to be balanced against the well known risk of adverse events especially in very young children.

[Antihistamines in allergic rhinitis]

Antihistamines are the first line of pharmacotherapy in allergic diseases, especially in allergic rhinitis. The article also presents the interesting 2005-2007 publications on the use of antihistamine in practical point of view, especially the newly introduced ones (desloratadine, fexofenadine, levocetirizine) and those which are to be introduced soon (rupatadine). The efficacy in skin histamine provocation model and various clinical model were discussed.

Safety of levocetirizine treatment in young atopic children: An 18-month study

There are more than 40 H(1)-antihistamines available worldwide. Most of these medications have never been optimally studied in prospective, randomized, double-masked, placebo-controlled trials in children. The aim was to perform a long-term study of levocetirizine safety in young atopic children. In the randomized, double-masked Early Prevention of Asthma in Atopic Children Study, 510 atopic children who were age 12-24 months at entry received either levocetirizine 0.125 mg/kg or placebo twice daily for 18 months. Safety was assessed by: reporting of adverse events, numbers of children discontinuing the study because of adverse events, height and body mass measurements, assessment of developmental milestones, and hematology and biochemistry tests. The population evaluated for safety consisted of 255 children given levocetirizine and 255 children given placebo. The treatment groups were similar demographically, and with regard to number of children with: one or more adverse events (levocetirizine, 96.9%; placebo, 95.7%); serious adverse events (levocetirizine, 12.2%; placebo, 14.5%); medication-attributed adverse events (levocetirizine, 5.1%; placebo, 6.3%); and adverse events that led to permanent discontinuation of study medication (levocetirizine, 2.0%; placebo, 1.2%). The most frequent adverse events related to: upper respiratory tract infections, transient gastroenteritis symptoms, or exacerbations of allergic diseases. There were no significant differences between the treatment groups in height, mass, attainment of developmental milestones, and hematology and biochemistry tests. The long-term safety of levocetirizine has been confirmed in young atopic children.

Prevention of asthma in childhood

PURPOSE OF REVIEW

The prevalence of asthma is increasing in many parts of the world, particularly in developed countries. The present review focuses on recent literature regarding asthma prevention in childhood.

RECENT FINDINGS

Several environmental exposures in infancy or early childhood are associated with reduced prevalence of asthma, but the mechanisms leading to these associations remain unknown. Recent studies have demonstrated limited success in the prevention of asthma or asthma symptoms with the use of asthma medications, once the therapy is discontinued. Immunotherapy offers another strategy for asthma prevention, and groups treated with this intervention have demonstrated reduced atopy and asthma. Several multi-interventional trials have demonstrated a reduced asthma symptom burden but have not demonstrated significant differences in objective measures such as lung function or bronchial hyper-responsiveness between intervention groups.

SUMMARY

The most promising asthma prevention strategies to date have been those that use a multi-interventional approach employing both dietary and environmental manipulations. More research is needed to assess the long-term follow-up of multi-interventional trials and to evaluate novel intervention strategies in the primary or secondary prevention of asthma in childhood.

Immunostimulants for preventing respiratory tract infection in children

BACKGROUND

Acute respiratory tract infections (ARTIs) are a major cause of childhood morbidity and mortality. Immunostimulants (IS) may reduce the incidence of ARTIs.

OBJECTIVES

To determine the efficacy and safety of IS in preventing ARTIs in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2005); MEDLINE (January 1966 to January 2006); and EMBASE (January 1990 to January 2006); PASCAL (up to January 2006); SciSearch (up to January 2006); and IPA (up to January 2006) for reports of trials. Investigators in the field were also contacted. Ongoing studies were searched in the trial registration web site, metaRegister of Controlled Trials.

SELECTION CRITERIA

All comparative trials which enrolled patients less than 18 years of age were included. The intervention of interest was the use of an IS medication administered by any method for preventing ARTIs. Clinical trials using random or quasi-random allocation and comparing IS medication or medications to placebo were included.

DATA COLLECTION AND ANALYSIS

The outcome on ARTIs was analyzed both as the mean number of ARTIs by group and as a percent change in the rate of ARTIs. Meta-analysis was undertaken using a random-effects model and results were presented as weighted mean differences (WMD) with 95% confidence intervals (CI). The trials search, quality assessment and data extraction were undertaken independently by two authors. A funnel plot suggested there may be publication bias in the trials identified.

MAIN RESULTS

Thirty-four placebo controlled trials (3877 participants) provided data in a form suitable for inclusion in the meta-analysis. When compared with placebo, the use of IS was shown to reduce ARTIs measured as the total numbers of ARTIs (WMD -1.27; 95% CI -1.58 to -0.97) and the difference in ARTIs rates (WMD -39.68%; 95% CI -47.27% to -32.09%). The trial quality was generally poor and a high level of statistical heterogeneity was evident. The subgroup analysis of bacterial IS studies produced similar results, with lower heterogeneity. No difference in adverse events was evident between the placebo and IS groups

AUTHORS' CONCLUSIONS

This review showed that IS reduces the incidence of ARTIs in children, by 40% on average. However, due to significant heterogeneity and the poor quality of the trials this positive result should be interpreted with caution. The safety profile of IS appears to be good. Further high-quality trials are needed and we encourage national health authorities to conduct large, multicenter, double-blind, placebo-controlled trials on the role of IS in the prevention of ARTIs.

Anti-histamines for prolonged non-specific cough in children

BACKGROUND

Non-specific cough is defined as non-productive cough in the absence of identifiable respiratory disease or known aetiology. It is commonly seen in paediatric practice. These children are treated with a variety of therapies including anti-histamines. Also, anti-histamines are advocated as an empirical treatment in adults with chronic cough.

OBJECTIVES

To evaluate the effectiveness of anti-histamines in treating children with prolonged non-specific cough.

SEARCH STRATEGY

The Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, OLDMEDLINE and EMBASE databases were searched by the Cochrane Airways Group. The latest searches were performed in November 2005.

SELECTION CRITERIA

All randomised controlled trials comparing anti-histamines with a placebo or placebo-like medication with cough as an outcome, where cough is not primarily related to an underlying respiratory disorder such as cystic fibrosis, asthma, or suppurative lung disease.

DATA COLLECTION AND ANALYSIS

Results of searches were reviewed against pre-determined criteria for inclusion. Two independent reviewers selected, extracted and assessed data for inclusion. Three eligible trials were identified.

MAIN RESULTS

The three included studies varied in age of subjects, sample size, inclusion criteria, type of anti-histamine and length of intervention. These 3 studies included 182 randomised subjects with 162 completing the trials although in one study, children with recurrent wheeze were also included. Clinical heterogeneity was evident and limited data prevented combining data for meta-analysis. The two larger studies described significant improvement in both the intervention and the placebo/placebo-like arms with no significant difference between the two groups. In the study with the smallest sample size, cetirizine (a second generation anti-histamine) was significantly more efficacious than placebo in reducing chronic cough in children associated with seasonal allergic rhinitis, and the effect was seen within 2 weeks of therapy.

AUTHORS' CONCLUSIONS

This review has significant limitations. However, our finding of uncertain efficacy of anti-histamines for chronic cough are similar to that for acute cough in children. In contrast to recommendations in adults with chronic cough, anti-histamines cannot be recommended as empirical therapy for children with chronic cough. If anti-histamines were to be trialled in these children, current data suggest a clinical response (time to response) occurs within 2 weeks of therapy. However the use of anti-histamines in children with non-specific cough has to be balanced against the well known risk of adverse events especially in very young children.