Is antihistamine (H1-receptor antagonist) therapy useful in clinical asthma?

Comorbid allergic rhinitis and asthma: important clinical considerations

INTRODUCTION

The numerous links between allergic rhinitis and asthma have been extensively explored in the last two decades, gaining great concern within the scientific community. These two conditions frequently coexist in the same patient and share numerous pathogenetic and pathophysiological mechanisms.

AREAS COVERED

We reviewed major pathophysiological, epidemiological, and clinical links between allergic rhinitis and asthma. We also provided a comprehensive discussion of allergic rhinitis treatment according to current guidelines, with a particular focus on the relevance of allergic rhinitis therapies in patients with comorbid asthma.

EXPERT OPINION

We believe that there are several unmet needs for our patients, however, there are promising advances forecasted for the future. Although allergic rhinitis is a recognized risk factor for asthma, a proper asthma detection and prevention plan in allergic rhinitis patients is not available. Allergen immunotherapy (AIT) represents a promising preventive strategy and may deserve an earlier positioning in allergic rhinitis management. A multidisciplinary approach should characterize the journey of patients with respiratory allergies, with an adequate referral to specialized Allergy/Asthma centers. Molecular Allergy Diagnosis may provide support for optimal AIT use. Finally, a possible evolution of biological treatment can be envisaged, mainly if biosimilars decrease such therapies' costs.

Management of adult asthma and chronic rhinitis as one airway disease

Introduction: Chronic rhinitis is defined as nasal inflammation with the presence of minimum two symptoms such as nasal obstruction, rhinorrhea, sneezing and/or itching one hour daily for a minimum of 12 weeks/year. According their etiology, four groups of rhinitis are described: allergic, infectious, non-allergic non-infectious and mixed.Chronic rhinitis is frequently associated with asthma, shares similar mechanisms of the pathogenesis and has a negative impact of its outcomes sustaining the concept of unified airways disease.Areas covered: The present review summarizes the complex relationship between chronic rhinitis and asthma on the basis of recent epidemiological data, clinical characteristics, diagnosis and therapeutic management. All four groups are discussed with the impact of their specific treatment on asthma outcomes. Some medications are common for chronic rhinitis and asthma while others are more specific but able to treat the associated comorbidity.Expert opinion: The systematic assessment of chronic rhinitis in patients with asthma and its specific treatment improves both disease outcomes. Conversely, several therapies of asthma demonstrated beneficial effects on chronic rhinitis. Treating both diseases at the same time by only one medication is an interesting option to explore in the future in order to limit drugs administration, related costs and side effects.

Current opinions for the management of asthma associated with ear, nose and throat comorbidities

Ear, nose and throat (ENT) comorbidities are common in patients with asthma and are frequently associated with poorer asthma outcomes. All these comorbidities are "treatable traits" in asthma. Identification and management of these disorders may spare medication usage and contribute to improved asthma control and quality of life, and a decrease in exacerbation rates.This review summarises recent data about the prevalence, clinical impact and treatment effects of ENT comorbidities in asthma including allergic rhinitis, chronic rhinosinusitis with and without nasal polyposis, aspirin-exacerbated respiratory disease, obstructive sleep apnoea and vocal cord dysfunction.Many of these comorbidities are possible to be managed by the pulmonologist, but the collaboration with the ENT specialist is essential for patients with chronic rhinosinusitis or vocal cord dysfunction. Further rigorous research is needed to study the efficacy of comorbidity treatment to improve asthma outcomes, in particular with the development of biotherapies in severe asthma that can also be beneficial in some ENT diseases.

Histamine H4 receptor mediates chemotaxis of human lung mast cells

The diverse effects of histamine are mediated by discrete histamine receptors. The principal repository of histamine in the body is the mast cell. However, the effects of histamine on mast cells, especially those of human origin, have not been fully elucidated. In this study, the expression of histamine receptors in human lung mast cells was evaluated. Moreover, the effects of histamine receptor engagement on both mediator release and chemotaxis were investigated. Mast cells were isolated and purified from human lung tissue. Histamine receptor expression was determined by RT-PCR and q-PCR. Both methods for the detection of histamine receptors were in accordance and human lung mast cells expressed mRNA for histamine H₄ and histamine H₁ receptors, variably expressed histamine H₂ receptor but did not express histamine H₃ receptor. The effects of selective histamine receptor agonists on the release of both pre-formed (histamine) and newly-synthesised (cysteinyl-leukotriene, prostaglandin D₂) mediators were investigated. None of the agonists tested had any direct effects on mediator release. None of the agonists modulated release stimulated by anti-IgE. Further studies showed that histamine induced migration of mast cells. Chemotaxis appeared to be mediated by the histamine H₄ receptor since JNJ28610244 (H₄ agonist) was chemotactic for mast cells whereas 2-(2-pyridyl) ethylamine (H₁ agonist) was not. Furthermore, the selective histamine H₄ receptor antagonist, JNJ7777120, effectively reversed the chemotaxis of mast cells induced by JNJ28610244. Overall, these experiments identify the histamine H₄ receptor as chemotactic for human lung mast cells. This mechanism might influence mast cell accumulation in the lung.

The Role of Histamine and Histamine Receptors in Mast Cell-Mediated Allergy and Inflammation: The Hunt for New Therapeutic Targets

Histamine and its receptors (H1R–H4R) play a crucial and significant role in the development of various allergic diseases. Mast cells are multifunctional bone marrow-derived tissue-dwelling cells that are the major producer of histamine in the body. H1R are expressed in many cells, including mast cells, and are involved in Type 1 hypersensitivity reactions. H2R are involved in Th1 lymphocyte cytokine production. H3R are mainly involved in blood–brain barrier function. H4R are highly expressed on mast cells where their stimulation exacerbates histamine and cytokine generation. Both H1R and H4R have important roles in the progression and modulation of histamine-mediated allergic diseases. Antihistamines that target H1R alone are not entirely effective in the treatment of acute pruritus, atopic dermatitis, allergic asthma, and other allergic diseases. However, antagonists that target H4R have shown promising effects in preclinical and clinical studies in the treatment of several allergic diseases. In the present review, we examine the accumulating evidence suggesting novel therapeutic approaches that explore both H1R and H4R as therapeutic targets for histamine-mediated allergic diseases.

The role of allergy immunotherapy in the treatment of asthma

PURPOSE OF REVIEW

Asthma and allergic rhinitis are two of the most widespread chronic medical conditions. Asthma, a condition which encompasses chronic inflammation of the lower airway resulting in expiratory obstruction, may represent an end phase along the allergic disease spectrum ultimately stemming initially from nasal allergic rhinitis and bronchial hyper-reactivity. The purpose of this review was to evaluate the available published literature over the past 12 months regarding the role of allergy immunotherapy in the treatment of asthma.

RECENT FINDINGS

Recent clinical trials, systematic reviews, and meta-analyses have demonstrated that allergen-specific immunotherapy (ASI), especially sublingual immunotherapy for as short as 12 months, may help improve asthma symptoms and reduce medication usage. However, studies have not demonstrated overall improvement in pulmonary function tests despite improvement in symptoms. Barriers to asthmatic patients initiating and maintaining ASI include lack of payment by health insurer, inconvenience, and potentially worsening asthma exacerbations/symptoms for patients with severe disease.

SUMMARY

ASI may change the natural course of allergic asthma by reducing the risk of acute respiratory exacerbations and symptoms. Additional studies are necessary to examine whether early treatment of allergy sensitivities with ASI may ultimately prevent the progression to asthma.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Coamorphous Loratadine-Citric Acid System with Enhanced Physical Stability and Bioavailability

Coamorphous systems using citric acid as a small molecular excipient were studied for improving physical stability and bioavailability of loratadine, a BCS class II drug with low water solubility and high permeability. Coamorphous loratadine-citric acid systems were prepared by solvent evaporation technique and characterized by differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Solid-state analysis proofed that coamorphous loratadine-citric acid system (1:1) was amorphous and homogeneous, had a higher T _g over amorphous loratadine, and the intermolecular hydrogen bond interactions between loratadine and citric acid exist. The solubility and dissolution of coamorphous loratadine-citric acid system (1:1) were found to be significantly greater than those of crystalline and amorphous form. The pharmacokinetic study in rats proved that coamorphous loratadine-citric acid system (1:1) could significantly improve absorption and bioavailability of loratadine. Coamorphous loratadine-citric acid system (1:1) showed excellently physical stability over a period of 3 months at 25°C under 0% RH and 25°C under 60% RH conditions. The improved stability of coamorphous loratadine-citric acid system (1:1) could be related to an elevated T _g over amorphous form and the intermolecular hydrogen bond interactions between loratadine and citric acid. These studies demonstrate that the developed coamorphous loratadine-citric acid system might be a promising oral formulation for improving solubility and bioavailability of loratadine.

Leukotriene Receptor Antagonists and Antiallergy Drugs

As one of the candidates of the therapeutic strategy for asthma in addition to inhaled corticosteroids (ICS), leukotriene receptor antagonists (LTRAs) are known to be useful for long-term management of asthma patients complicated by allergic rhinitis (AR) or exercise-induced asthma (EIA). Currently available LTRAs are pranlukast hydrate, zafirlukast, and montelukast. These LTRAs have a bronchodilator action and inhibit airway inflammation, resulting in a significant improvement of asthma symptoms, respiratory function, inhalation frequency of as-needed inhaled β2-agonist, airway inflammation, airway hyperresponsiveness, dosage of ICSs, asthma exacerbations, and patients' QOL. Although cys-LTs are deeply associated with the pathogenesis of asthma, LTRAs alone are less effective compared with ICS. However, the effects of LTRAs in combination with ICS are the same as those of LABAs in combination with ICS in steroid-naïve asthmatic patients. Concerning antiallergy drugs other than LTRAs, some mediator-release suppressants, H1 histamine receptor antagonists (H1RAs), thromboxane A2 (TXA2) inhibitors/antagonists, and Th2 cytokine inhibitor had been used mainly in Japan until the late 1990s. However, the use of these agents rapidly decreased after ICS/long acting beta agonist (LABA) combination was introduced and recommended for the management of asthma in the early 2000s. The effectiveness of other antiallergic agents on asthma management seems to be quite limited, and the safety of oral antiallergic agents has not been demonstrated in fetuses during pregnancy. Further effectiveness studies are needed to determine the true value of these orally administered agents in combination with ICS as an anti-asthma treatment.

International Union of Basic and Clinical Pharmacology. XCVIII. Histamine Receptors

Histamine is a developmentally highly conserved autacoid found in most vertebrate tissues. Its physiological functions are mediated by four 7-transmembrane G protein-coupled receptors (H1R, H2R, H3R, H4R) that are all targets of pharmacological intervention. The receptors display molecular heterogeneity and constitutive activity. H1R antagonists are long known antiallergic and sedating drugs, whereas the H2R was identified in the 1970s and led to the development of H2R-antagonists that revolutionized stomach ulcer treatment. The crystal structure of ligand-bound H1R has rendered it possible to design new ligands with novel properties. The H3R is an autoreceptor and heteroreceptor providing negative feedback on histaminergic and inhibition on other neurons. A block of these actions promotes waking. The H4R occurs on immuncompetent cells and the development of anti-inflammatory drugs is anticipated.

Improvement and prevention of asthma with concomitant treatment of allergic rhinitis and allergen-specific therapy

BACKGROUND

Asthma and allergic rhinitis are 2 of the most prevalent chronic medical diseases. Asthma is estimated to affect 8% of adults and 9% of children, with nearly 300 million people affected worldwide. Poorly controlled allergic rhinitis may be associated with worsening asthma symptoms over time. Various treatments have been proposed in the improvement and prevention of asthma in children and adults with allergic symptoms, which have included pharmacotherapy with antihistamines and topical intranasal corticosteroids, as well as allergen-specific immunotherapy.

METHODS

Articles were selected through PubMed and personal knowledge of the authors based on a comprehensive literature review examining whether treatment of allergic rhinitis improves and/or prevents concomitant symptoms of asthma. The largest and highest-quality studies were included in the literature review. The search selection was not standardized. Articles written in a language other than English were excluded.

RESULTS

Clinical trials have showed improvement in asthma symptoms with concomitant treatment of allergic rhinitis with antihistamines and topical intranasal corticosteroids, though improvement in objective pulmonary function parameters has not been uniformly demonstrated with antihistamine use alone. There is very strong evidence to suggest that subcutaneous and sublingual immunotherapy may in addition prevent the progression of asthma in high-risk atopic patients by inducing immunological tolerance.

CONCLUSION

Traditional pharmacotherapy with antihistamines and topical intranasal steroids has been shown to improve allergic rhinitis symptoms with concomitant allergic asthma; however, only allergen-specific immunotherapy offers long-term control in improving asthma symptoms, exacerbations, and likely ultimate prevention in developing asthma.

The effect of rupatadine on lung histopathology in a murine model of chronic asthma

INTRODUCTION

Rupatadine is a new second-generation antihistamine with H(1) receptor antagonist activity and platelet-activating factor antagonist properties. This study aimed to investigate the effect of rupatadine on histologic changes in the lungs in a murine model of chronic asthma.

MATERIALS AND METHODS

Thirty-five BALB/c mice were divided into five groups of seven mice each: group I (control), group II (placebo [saline]), group III (dexamethasone 1 mg · kg(-1)·d(-1)), group IV (rupatadine 3 mg·kg(-1) d(-1)), and group V (rupatadine 30 mg·kg(-1)·d(-1)). Groups II through V were sensitized and challenged with ovalbumin and treated once per day via the oral route (gavage). Animals were sacrificed 24 h after the last treatment was administered. Airway histopathology was evaluated using light and electron microscopy in all groups.

RESULTS

There were no significant differences observed in any of the histologic parameters between groups II and IV. There were significantly thinner basement membrane, subepithelial smooth muscle layer, and epithelia were significantly thinner in group V than in group II (p < .05). There were no statistically significant differences in the thicknesses of the basement membrane, subepithelial smooth muscle layer and epithelia between groups III and V.

CONCLUSION

Rupatadine had a beneficial effect on histologic changes in a chronic murine model of asthma.

Comparison of cetirizine-pseudoephedrine and placebo in patients with seasonal allergic rhinitis and concomitant mild-to-moderate asthma: randomized, double-blind study

BACKGROUND

Allergic rhinitis (AR) and asthma are common concurrent conditions.

OBJECTIVES

To evaluate the effects of cetirizine hydrochloride (5 mg)-pseudoephedrine hydrochloride (120 mg) (cetirizine-D) twice daily on AR and asthma symptoms, pulmonary function, and asthma-related quality of life in 274 patients with confirmed seasonal AR and concomitant mild-to-moderate asthma.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled study, after a 1-week screening period, patients took cetirizine-D or placebo for 4 weeks. The primary efficacy variable, AR total symptom severity complex score, was derived from patient daily diary ratings of sneezing, runny nose, itchy nose, postnasal drip, and nasal congestion. Asthma symptom severity total scores were derived from twice-daily diary ratings of wheezing, coughing, shortness of breath, and chest tightness. Pulmonary function was tested at clinic visits and by patients each morning and evening. Patients completed the Asthma Quality of Life Questionnaire at each visit. All tests were 2-sided, with statistical significance at the .05 level.

RESULTS

Cetirizine-D reduced total symptom severity complex scores by 42.3% overall vs 23.6% with placebo (P < .001). Asthma symptom severity total scores were significantly improved with cetirizine-D at most times vs placebo. Cetirizine-D treatment was also associated with significantly improved Asthma Quality of Life Questionnaire overall scores. Pulmonary function test results were neutral. Cetirizine-D was well tolerated, with discontinuation and adverse event rates similar to placebo. Somnolence occurred in 8 patients (5.8%) taking cetirizine-D and in 1 (0.7%) taking placebo.

CONCLUSIONS

Treatment with cetirizine-D twice daily significantly reduced rhinitis and asthma symptoms and improved overall asthma quality of life in patients with seasonal AR and concomitant mild-to-moderate asthma.

Histamine receptors are hot in immunopharmacology

In addition to its well-characterized effects in the acute allergic inflammatory responses, histamine has been demonstrated to affect chronic inflammation and regulate several essential events in the immune response. Histamine can selectively recruit the major effector cells into tissue sites and affect their maturation, activation, polarization, and other functions leading to chronic inflammation. Histamine also regulates dendritic cells, T cells and B cells, as well as related antibody isotype responses. In addition, acting through its receptor 2, histamine positively interferes with the peripheral antigen tolerance induced by T regulatory cells in several pathways. The diverse effects of histamine on immune regulation appear to be due to differential expression and regulation of 4 types of histamine receptors and their distinct intracellular signals. In addition, differences in affinities of these receptors for histamine is highly decisive for the biological effects of histamine and drugs that target histamine receptors. This article highlights recent discoveries in histamine immunobiology and discusses their relevance in allergic inflammation.

Intranasal and inhaled fluticasone propionate for pollen-induced rhinitis and asthma

BACKGROUND

Studies suggest that nasal treatment might influence lower airway symptoms and function in patients with comorbid rhinitis and asthma. We investigated the effect of intranasal, inhaled corticosteroid or the combination of both in patients with both pollen-induced rhinitis and asthma.

METHODS

A total of 262 patients were randomized to 6 weeks' treatment with intranasal fluticasone propionate (INFP) 200 microg o.d., inhaled fluticasone propionate (IHFP) 250 microg b.i.d., their combination, or intranasal or inhaled placebo, in a multicentre, double-blind, parallel-group study. Treatment was started 2 weeks prior to the pollen season and patients recorded their nasal and bronchial symptoms twice daily. Before and after 4 and 6 weeks' treatment, the patients were assessed for lung function, methacholine responsiveness, and induced sputum cell counts.

RESULTS

Intranasal fluticasone propionate significantly increased the percentages of patients reporting no nasal blockage, sneezing, or rhinorrhoea during the pollen season, compared with IHFP or intranasal or inhaled placebo. In contrast, only IHFP significantly improved morning peak-flow, forced expiratory volume in 1 second (FEV1) and methacholine PD20, and the seasonal increase in the sputum eosinophils and methacholine responsiveness.

CONCLUSIONS

In patients with pollen-induced rhinitis and asthma, the combination of intranasal and IHFP is needed to control the seasonal increase in nasal and asthmatic symptoms.

Effects of first and second generation antihistamines on muscarinic induced mucus gland cell ion transport

Background

The first generation antihistamines, such as diphenhydramine, are fairly potent muscarinic antagonists in addition to being H1 selective antihistamines. The antimuscarinic action is often not desirable since it is in part responsible for the drying of secretions in the airways and the sedative effect. We therefore examined a number of antihistamines for antimuscarinic effects on ion transport by mucus gland cells isolated from the airways of swine. Enzymatically isolated airway mucus gland cells were purified utilizing density gradients and grown in culture on porous inserts (Millicell HA™) at an air interface. Cells grown in this manner maintain phenotype and polarity. Transport of ions, as short-circuit current measured under voltage-clamp, was measured in response to acetylcholine (ACh) or histamine applied to the serosal side of the gland cell layers. Concentration-response relationships for ACh or histamine were generated in the presence and absence of various drugs. The potencies against muscarinic receptor activation were estimated using the dose-ratio method of Schild.

Results

Three known muscarinic antagonists were used to validate the system. Atropine had a pA₂ of 9.4 ± 0.1 (n = 9). 4-DAMP and methoctramine had pA₂ values of 8.6 ± 0.1 and 5.6 ± 0.1, respectively (n = 12, 11) all consistent with inhibition of an M3 subtype muscarinic receptor. The rank order of potency of the antihistamines against the inhibition of M3 receptors was desloratadine = diphenhydramine > hydroxyzine (pA₂; 6.4, 6.2, 4.8, respectively). pA₂ values for fexofenadine, loratadine and cetirizine were not determined since they had no effect on the cholinergic response at the highest drug concentrations tested (10, 10 and 100 μM, respectively). The pA₂ values for the antihistamines against the histamine response could not be calculated, but the estimates of the rank order of potency were estimated to be desloratadine> cetirizine ≈ hydroxyzine > fexofenadine > loratadine > diphenhydramine.

Conclusion

The rank order of selectivity for histamine receptors over muscarinic receptors was estimated to be cetirizine ≈ fexofenadine > loratadine > desloratadine ≥ hydroxyzine ≥ diphenhydramine.

Rhinitis therapy and the prevention of hospital care for asthma: a case-control study

BACKGROUND

Although clinical trials have demonstrated that rhinitis therapy improves subjective and objective measures of asthma, it is uncertain whether treatment of allergic rhinitis significantly affects the frequency of asthma exacerbations.

OBJECTIVE

The objective of this study was to determine whether treatment with intranasal corticosteroids and/or second-generation antihistamines is associated with changes in rates of asthma exacerbations resulting in emergency room visits and/or hospitalizations in patients with asthma and allergic rhinitis.

METHODS

This was a nested, case-control study.

RESULTS

Treatment with either nasal corticosteroids or second-generation antihistamines was associated with a lower risk of asthma-related emergency room treatment and hospitalization (adjusted odds ratio [OR], 0.51; 95% CI, 0.34 to 0.77 and 0.34, 0.18 to 0.62, respectively). Patients who used nasal corticosteroids had a significantly lower risk of both asthma-related emergency room treatment and hospitalization (adjusted OR, 0.75; 95% CI, 0.62 to 0.91 and 0.56, 0.42 to 0.76, respectively), whereas there was a trend toward lower risk of emergency room treatment and hospitalization in patients who used second-generation antihistamines (adjusted OR, 0.88; 95% CI, 0.62 to 1.26 and 0.68, 0.40 to 1.14, respectively). Combined treatment with both medications was associated with a further lowering of the risk of both emergency room treatment and hospitalization (adjusted OR, 0.37; 95% CI, 0.19 to 0.73 and 0.22, 0.07 to 0.63).

CONCLUSIONS

In patients with asthma, treatment of concomitant allergic rhinitis was associated with significant reductions in risk of emergency room treatment and hospitalization for asthma.

H1-Antihistamines: more relevant than ever in the treatment of allergic disorders

Histamine is an important chemical mediator of inflammation, vasodilation, increased vascular permeability, decreased peripheral resistance, airway smooth muscle contraction, and sensory nerve stimulation causing itching. It also plays a significant role in neurotransmission and in cardiac function. In allergic rhinoconjunctivitis and urticaria, there is strong evidence for the role of H(1)-antihistamine treatment. In asthma, additional dose-response studies, including higher doses of antihistamines than those used in allergic rhinitis, are needed to determine the role of antihistamines. In atopic dermatitis, the itch-relieving topical glucocorticoid-sparing effects of H(1)-antihistamines also require further documentation. The potential benefits of each H(1)-antihistamine should be weighed against the potential risks, and second-generation H(1)-antihistamines with excellent, well-documented safety records should be used in preference to older, less safe H(1)-antihistamines. Second-generation H(1)-antihistamines are more relevant than ever in the treatment of allergic disorders.

Oxatomide for stable asthma in adults and children

BACKGROUND

Oxatomide is a histamine H1-receptor antagonist. As an oral agent, oxatomide may be useful in managing asthma. Some guidelines recommend oxatomide for long-term prophylaxis of asthma in children. There is no clear evidence whether children or adults with asthma benefit from oxatomide.

OBJECTIVES

To determine whether oxatomide alone, or in combination with other interventions, results in better disease control in people with asthma.

SEARCH STRATEGY

The Collaborative Airway Group register and Collaborations trial register CENTRAL were searched using terms: oxatomide* OR Celtect OR Pinset OR KW-4354 OR Tincet. Reference lists of all relevant trials or review articles were checked. Enquiries were made of authors of included studies and relevant pharmaceutical companies. A search of 'Igaku Chuo Zasshi' and 'J-Medicine' were made using the following terms: oxatomide (also in Japanese) or Celtect (also in Japanese) or KW-4354.

SELECTION CRITERIA

Studies were randomised, placebo-controlled trials and the interventions were oxatomide or matched placebo given alone or in combination with other asthma-medication for at least 4 weeks.

DATA COLLECTION AND ANALYSIS

Four independent reviewers performed assessments of methodological quality and extracted relevant data.

MAIN RESULTS

Six studies are included in this review. Three studies were mainly conducted in adults, two were conducted in older children (5-16 years) and one in infants (18-25 months). Trial duration was 4 to 52 weeks. Doses of oxatomide varied between studies, ranging from 1 mg/kg/day for infants to 180 mg/day for adults. Only data on adverse events was suitable for meta-analysis. Although PEF did not change significantly in any of the studies, the FVC and FEV1 improved significantly in two. There was no uniform change in symptom scores. There was no significant difference between oxatomide and placebo treatment in use of inhaled corticosteroid or bronchodilator. Two studies showed significant improvement with oxatomide as judged subjectively by physicians. Adverse events, analysed using data from 4 parallel and one cross over study, showed oxatomide to be associated with a significantly higher risk of any adverse event (OR: 2.97, 95%CI: 1.69 to 5.22) and drowsiness (OR: 5.22,95%CI: 2.53 to 10.74).

REVIEWER'S CONCLUSIONS

There is no evidence to show that oxatomide has a significant effect on the control of stable asthma. Some studies reported significant benefits in subjective parameters. There was improvement in some lung function outcomes reported, but this were not consistent across measures or studies and may represent reporting bias. Adverse events, including drowsiness, were significantly greater with oxatomide than placebo.

Drug therapy approaches in the treatment of acute severe asthma in hospitalised children

Acute severe paediatric asthma remains a serious and debilitating disease throughout the world. The incidence and mortality from asthma continue to increase. Early, effective and aggressive outpatient therapy is essential in reducing symptoms and preventing life-threatening progression. When complications occur or when the disease progresses to incipient respiratory failure, these children need to be managed in a continuous care facility where aggressive and potentially dangerous interventions can be safely instituted to reverse persistent bronchospasm. The primary drugs for acute severe asthma include oxygen, corticosteroids, salbutamol (albuterol) and anticholinergics. Second-line drugs include heliox, magnesium sulfate, ketamine and inhalational anaesthetics. Future therapies may include furosemide, leukotriene modifiers, antihistamines and phosphodiesterase inhibitors. This review attempts to explore the multitude of medications available with emphasis on pharmacology and pathophysiology.