A randomized controlled trial on the effect of montelukast on sputum eosinophil cationic protein in children with corticosteroid-dependent asthma

Montelukast in paediatric asthma and allergic rhinitis: a systematic review and meta-analysis

BACKGROUND

We aim to assess the impact of montelukast on paediatric patients with asthma/allergic rhinitis, measured using patient-reported outcome measures, compared with other treatments or placebo.

METHODS

Protocol registration CRD42020216098 (www.crd.york.ac.uk/PROSPERO). MEDLINE and Embase databases were used to conduct the search. Two authors independently selected studies and extracted data, and a third reviewer resolved discrepancies. Meta-analyses were constructed to estimate the standardised mean difference (SMD) using a random-effects model.

RESULTS

Out of 3937 articles identified, 49 studies met the inclusion criteria, mostly randomised clinical trials (sample sizes: 21-689 patients). The SMD of change pooled estimators for the global, mental and physical domains of health-related quality of life were not statistically significant. For daytime and night-time symptoms scores, the SMD (95% CI) was in favour of inhaled corticosteroids (-0.12, -0.20- -0.05 and -0.23, -0.41- -0.06, respectively). The pooled estimator for global asthma symptoms was better for montelukast when compared with placebo (0.90, 0.44-1.36).

CONCLUSIONS

The synthesis of the available evidence suggests that, in children and adolescents, montelukast was effective in controlling asthma symptoms when compared with placebo, but inhaled corticosteroids were superior in controlling symptoms, especially at night-time. These findings of our systematic review concur with current guidelines for asthma treatment.

Best step-up treatments for children with uncontrolled asthma: a systematic review and network meta-analysis of individual participant data

BACKGROUND

There is uncertainty about the best treatment option for children/adolescents with uncontrolled asthma despite inhaled corticosteroids (ICS) and international guidelines make different recommendations. We evaluated the pharmacological treatments to reduce asthma exacerbations and symptoms in uncontrolled patients age <18 years on ICS.

METHODS

We searched MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Embase, Web of Science, National Institute for Health and Care Excellence Technology Appraisals, National Institute for Health and Care Research Health Technology Assessment series, World Health Organization International Clinical Trials Registry, conference abstracts and internal clinical trial registers (1 July 2014 to 5 May 2023) for randomised controlled trials of participants age <18 years with uncontrolled asthma on any ICS dose alone at screening. Studies before July 2014 were retrieved from previous systematic reviews/contact with authors. Patients had to be randomised to any dose of ICS alone or combined with long-acting β2-agonists (LABA) or combined with leukotriene receptor antagonists (LTRA), LTRA alone, theophylline or placebo. Primary outcomes were exacerbation and asthma control. The interventions evaluated were ICS (low/medium/high dose), ICS+LABA, ICS+LTRA, LTRA alone, theophylline and placebo.

RESULTS

Of the 4708 publications identified, 144 trials were eligible. Individual participant data were obtained from 29 trials and aggregate data were obtained from 19 trials. Compared with ICS Low, ICS Medium+LABA was associated with the lowest odds of exacerbation (OR 0.44, 95% credibility interval (95% CrI) 0.19-0.90) and with an increased forced expiratory volume in 1 s (mean difference 0.71, 95% CrI 0.35-1.06). Treatment with LTRA was the least preferred. No apparent differences were found for asthma control.

CONCLUSIONS

Uncontrolled children/adolescents on low-dose ICS should be recommended a change to medium-dose ICS+LABA to reduce the risk for exacerbation and improve lung function.

Novel montelukast sodium-loaded stable oral suspension bioequivalent to the commercial granules in rats

To develop a montelukast sodium-loaded stable oral suspension bioequivalent to the commercial granules in rats, several montelukast sodium-loaded suspensions were prepared with a suspending agent, stabilizers and anti-aggregation agents, and their stabilities were investigated by visually observing the sedimentation phenomenon and determining the concentration of the degradation product. Moreover, dissolution and pharmacokinetic studies of the optimized formulation were examined in rats compared to commercial montelukast sodium-loaded granules. Avicel RC-591 (Avicel), a suspending agent, prevented the sedimentation of these suspensions at >2.496 (w/v) per cent composition. Amongst the stabilizers tested, fumaric acid provided the lowest concentration of montelukast sulphoxide (a degradation product) in these suspensions at 40 °C, demonstrating its excellent stabilizing activity. Furthermore, as an anti-aggregation agent, glycerin gave lower amounts of degradation product than those with poloxamer 407 and Tween 80. In particular, montelukast-loaded oral suspension, an aqueous suspension containing montelukast sodium/Avicel/fumaric acid/glycerin at a concentration of 312/2496/15.6/62.4 (mg/100 ml), and the commercial granules exhibited similar dissolution profiles in 0.5% (w/v) aqueous solution of sodium lauryl sulphate. Moreover, the pharmacokinetics in rats provided by this suspension was comparable to that of the commercial granules, suggesting that they were bioequivalent. In addition, it was physically and chemically stable at 40 °C for at least 6 months. Thus, this montelukast sodium-loaded oral suspension, with bioequivalence to the commercial granules and excellent stability, could be a prospective dosage form for the treatment of asthma.

Effect of montelukast on clinical score and cytokine levels of infants for clinically diagnosed acute bronchiolitis

BACKGROUND

Acute bronchiolitis comprises a major cause for morbidity in infants with viral infection which induces an immune inflammatory response that may produce long lasting harmful effects. Currently, there is no effective therapy for bronchiolitis.

OBJECTIVE

Our aim was to investigate the efficacy of five-day montelukast therapy in acute bronchiolitis management.

METHODS

The study included 50 infants with acute bronchiolitis. The infants with first episode of acute bronchiolitis were randomly assigned to receive daily montelukast dose of 4mg over five days after admission or no treatment. Plasma eotaxin, IL-4, IL-8 and IFN-gamma levels were evaluated before and after treatment by ELISA method. In the present study, the primary outcome measure was change in clinical severity score, whilst secondary outcome measures were changes in plasma eotaxin, IL-4, IL-8, IFN-gamma levels.

RESULTS

No significant differences was found in clinical severity score with five-day montelukast treatment (p>0.05, Mann-Whitney U test). There were no significant differences in plasma eotaxin, IL-4, IL-8, IFN-gamma levels between the groups (p>0.05 Mann-Whitney U test). There was significant decrease in plasma IFN-gamma levels following five-day montelukast treatment (p=0.027, Wilcoxon). There were no significant differences in plasma IL-4, IL-8, IFN-gamma levels between the groups after five-day montelukast treatment (p>0.05, Wilcoxon). There was significant increase in eotaxin levels after five-day montelukast treatment (p=0.009, Wilcoxon).

CONCLUSION

Our study showed that montelukast affected plasma IFN-gamma and eotaxin levels after five days of treatment. Further studies are needed to demonstrate effects of montelukast on chemokine levels in bronchiolitis.

Which biomarkers are effective for identifying Th2-driven inflammation in asthma?

Recognition of asthma as a heterogeneous disease revealed different potential molecular targets and urged the development of targeted, customized treatment modalities. Evidence was provided for different inflammatory subsets of asthma and more recently, further refined to T helper (Th)2-high and Th2-low subphenotypes with different responsiveness to standard and targeted pharmacotherapy. Given these differences in immunology and pathophysiology, proof of concept studies of novel treatment modalities for asthma should be performed in adequate, well-defined phenotypes. In this review, we describe both existing and novel biomarkers of Th2-inflammation in asthma that can be applied to classify asthma subphenotypes in clinical studies and for treatment monitoring.

Addition of anti-leukotriene agents to inhaled corticosteroids in children with persistent asthma

BACKGROUND

In the treatment of children with mild persistent asthma, low-dose inhaled corticosteroids (ICS) are recommended as the preferred monotherapy (referred to as step 2 of therapy). In children with inadequate asthma control on low doses of ICS (step 2), asthma management guidelines recommend adding an anti-leukotriene agent to existing ICS as one of three therapeutic options to intensify therapy (step 3).

OBJECTIVES

To compare the efficacy and safety of the combination of anti-leukotriene agents and ICS to the use of the same, an increased, or a tapering dose of ICS in children and adolescents with persistent asthma who remain symptomatic despite the use of maintenance ICS. In addition, we wished to determine the characteristics of people or treatments, if any, that influenced the magnitude of response attributable to the addition of anti-leukotrienes.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of Trials (CAGR), which were derived from systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, AMED, and CINAHL; and the handsearching of respiratory journals and meeting abstracts, as well as the www.clinicaltrials.gov website. The search was conducted until January 2013.

SELECTION CRITERIA

We considered for inclusion randomised controlled trials (RCTs) conducted in children and adolescents, aged one to 18 years, with asthma, who remained symptomatic despite the use of a stable maintenance dose of ICS and in whom anti-leukotrienes were added to the ICS if they were compared to the same, an increased, or a tapering dose of ICS for at least four weeks.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

Five paediatric (parallel group or cross-over) trials met the inclusion criteria. We considered two (40%) trials to be at a low risk of bias. Four published trials, representing 559 children (aged ≥ six years) and adolescents with mild to moderate asthma, contributed data to the review. No trial enrolled preschoolers. All trials used montelukast as the anti-leukotriene agent administered for between four and 16 weeks. Three trials evaluated the combination of anti-leukotrienes and ICS compared to the same dose of ICS alone (step 3 versus step 2). No statistically significant group difference was observed in the only trial reporting participants with exacerbations requiring oral corticosteroids over four weeks (N = 268 participants; risk ratio (RR) 0.80, 95% confidence interval (CI) 0.34 to 1.91). There was also no statistically significant difference in percentage change in FEV₁ (forced expiratory volume in 1 second) with mean difference (MD) 1.3 (95% CI -0.09 to 2.69) in this trial, but a significant group difference was observed in the morning (AM) and evening (PM) peak expiratory flow rates (PEFR): N = 218 participants; MD 9.70 L/min (95% CI 1.27 to 18.13) and MD 10.70 (95% CI 2.41 to 18.99), respectively. One trial compared the combination of anti-leukotrienes and ICS to a higher-dose of ICS (step 3 versus step 3). No significant group difference was observed in this trial for participants with exacerbations requiring rescue oral corticosteroids over 16 weeks (N = 182 participants; RR 0.82, 95% CI 0.54 to 1.25), nor was there any significant difference in exacerbations requiring hospitalisation. There was no statistically significant group difference in withdrawals overall or because of any cause with either protocol. No trial explored the impact of adding anti-leukotrienes as a means to taper the dose of ICS.

AUTHORS' CONCLUSIONS

The addition of anti-leukotrienes to ICS is not associated with a statistically significant reduction in the need for rescue oral corticosteroids or hospital admission compared to the same or an increased dose of ICS in children and adolescents with mild to moderate asthma. Although anti-leukotrienes have been licensed for use in children for over 10 years, the paucity of paediatric trials, the absence of data on preschoolers, and the variability in the reporting of relevant clinical outcomes considerably limit firm conclusions. At present, there is no firm evidence to support the efficacy and safety of anti-leukotrienes as add-on therapy to ICS as a step-3 option in the therapeutic arsenal for children with uncontrolled asthma symptoms on low-dose ICS.

Role of leukotriene receptor antagonists in the management of pediatric asthma: an update

At present, the main indications for leukotriene receptor antagonists (LTRA) in pediatric asthma are as add-on therapy to inhaled corticosteroids (ICS) and as initial controller therapy in children with mild asthma, especially those who cannot or will not use ICS. LTRA are also useful for patients who have concomitant rhinitis, and patients with viral-induced wheeze and exercise-induced asthma. It should be noted that the benefits of LTRA therapy have been demonstrated in children as young as 6 months of age and recent clinical trials have further proven the benefits of LTRA in acute asthma exacerbations. However, considering the important pro-inflammatory effects that leukotrienes (LT) have in experimental models of asthma, it may seem surprising that LTRA treatment outcomes are not better and that in some clinical trials only a minority of patients could be classified as full responders. This could be explained by potential additional LT receptors that are not affected by LTRA. Such receptors could represent new therapeutic targets in asthma. Furthermore, progress in differentiating between asthma phenotypes that result from different pathogenic mechanisms, some of which may involve LT to a lesser degree, should lead to an improved, personalized use of LTRA for treating asthma.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes (5-lipoxygenase inhibitors and leukotriene receptors antagonists) serve as alternative monotherapy to inhaled corticosteroids (ICS) in the management of recurrent and/or chronic asthma in adults and children.

OBJECTIVES

To determine the safety and efficacy of anti-leukotrienes compared to inhaled corticosteroids as monotherapy in adults and children with asthma and to provide better insight into the influence of patient and treatment characteristics on the magnitude of effects.

SEARCH METHODS

We searched MEDLINE (1966 to Dec 2010), EMBASE (1980 to Dec 2010), CINAHL (1982 to Dec 2010), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (Dec 2010), abstract books, and reference lists of review articles and trials. We contacted colleagues and the international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

We included randomised trials that compared anti-leukotrienes with inhaled corticosteroids as monotherapy for a minimum period of four weeks in patients with asthma aged two years and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data. The primary outcome was the number of patients with at least one exacerbation requiring systemic corticosteroids. Secondary outcomes included patients with at least one exacerbation requiring hospital admission, lung function tests, indices of chronic asthma control, adverse effects, withdrawal rates and biological inflammatory markers.

MAIN RESULTS

Sixty-five trials met the inclusion criteria for this review. Fifty-six trials (19 paediatric trials) contributed data (representing total of 10,005 adults and 3,333 children); 21 trials were of high methodological quality; 44 were published in full-text. All trials pertained to patients with mild or moderate persistent asthma. Trial durations varied from four to 52 weeks. The median dose of inhaled corticosteroids was quite homogeneous at 200 µg/day of microfine hydrofluoroalkane-propelled beclomethasone or equivalent (HFA-BDP eq). Patients treated with anti-leukotrienes were more likely to suffer an exacerbation requiring systemic corticosteroids (N = 6077 participants; risk ratio (RR) 1.51, 95% confidence interval (CI) 1.17, 1.96). For every 28 (95% CI 15 to 82) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional patient with an exacerbation requiring rescue systemic corticosteroids. The magnitude of effect was significantly greater in patients with moderate compared with those with mild airway obstruction (RR 2.03, 95% CI 1.41, 2.91 versus RR 1.25, 95% CI 0.97, 1.61), but was not significantly influenced by age group (children representing 23% of the weight versus adults), anti-leukotriene used, duration of intervention, methodological quality, and funding source. Significant group differences favouring inhaled corticosteroids were noted in most secondary outcomes including patients with at least one exacerbation requiring hospital admission (N = 2715 participants; RR 3.33; 95% CI 1.02 to 10.94), the change from baseline FEV(1) (N = 7128 participants; mean group difference (MD) 110 mL, 95% CI 140 to 80) as well as other lung function parameters, asthma symptoms, nocturnal awakenings, rescue medication use, symptom-free days, the quality of life, parents' and physicians' satisfaction. Anti-leukotriene therapy was associated with increased risk of withdrawals due to poor asthma control (N = 7669 participants; RR 2.56; 95% CI 2.01 to 3.27). For every thirty one (95% CI 22 to 47) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional withdrawal due to poor control. Risk of side effects was not significantly different between both groups.

AUTHORS' CONCLUSIONS

As monotherapy, inhaled corticosteroids display superior efficacy to anti-leukotrienes in adults and children with persistent asthma; the superiority is particularly marked in patients with moderate airway obstruction. On the basis of efficacy, the results support the current guidelines' recommendation that inhaled corticosteroids remain the preferred monotherapy. 

Comparative clinical evaluation of ketotifen and montelukast sodium in asthmatic Iraqi patients

Asthma is a common and chronic inflammatory condition of the airways whose cause is not completely understood. Although many classes of drugs are used for management of asthma, the response is variable due to multifactor reasons. This study was designed to evaluate the outcome of using ketotifen or montelukast sodium in Iraqi asthmatic patients. Single blinded randomized clinical trial was utilized, in which 100 asthmatic patients were recruited from Al-Karama hospital and randomized into two groups; 1st group (50 patients, treated with ketotifen for 4 weeks) and 2nd group (50 patients treated with montelukast sodium for 4 weeks). Asthma symptom score and wheezing were recorded at the beginning (first visit) and at the end of the study (after one month). Pulmonary function tests (PFTs) were performed by spirometry, and the patients' use of asthma drugs and their symptoms were evaluated at each visit. The result showed that asthma symptom, chest wheezing, and PFT values were significantly improved in the two groups at the end of the study compared to first visit (p < 0.05). All symptoms were significantly lower and PFT values were higher in the 2nd group compared to 1st group (p < 0.05). In conclusion, both ketotifen and montelukast sodium showed significant changes in asthma symptoms and PFT after one month of treatment, but the changes were more significant with montelukast group (2nd group) compared with ketotifen group (1st group) and this indicate that montelukast was more effective than ketotifen in treatment of asthmatic patients.

Leukotriene modifiers in the treatment of asthma in children

Asthma is one of the most common respiratory disorders in clinical practice, affecting up to 13% of people worldwide. Inflammation is the most important component of asthma and inhaled corticosteroids (ICS) are recommended as the first line controller treatment for patients of all ages. Treatment with corticosteroids is often unable to fully control asthma symptoms and progression. Recently, leukotrienes have come to the forefront of research as they have been found play a pivotal role in the airway inflammatory process, and specific drugs have been developed to target them. Cysteiny leukotriene antagonists (LTRAs) have recently emerged as important therapeutic options that show a large potential clinical utility. Three specific LTRAs are licensed for clinical use: montelukast, zafirlukast and pranlukast, although montelukast is the only drug approved in the paediatric age range. It is well tolerated (although adverse effects such as headaches, abdominal pain, rashes, angioedema, pulmonary eosinophilia and arthralgia have been reported) and shows many positive effects in asthmatic patients. Current Global Initiative for Asthma guidelines recommend LTRAs as: (1) a second choice treatment to ICS for patients with mild persistent asthma, (2) an add-on therapy to reduce the dose of ICS in patients with moderate or severe asthma, due to the different and complementary mechanisms of action of these agents. LTRAs may be particularly appropriate choices in a number of clinical situations, including the following: patients with concomitant rhinitis; patients with viral-induced wheeze; patients with exercise-induced bronchoconstriction (EIB) and, in children aged 2-5 years, to reduce the frequency of asthma exacerbations.

Montelukast inhibits tumour necrosis factor-alpha-mediated interleukin-8 expression through inhibition of nuclear factor-kappaB p65-associated histone acetyltransferase activity

BACKGROUND

Montelukast is a potent cysteinyl leukotriene-1 receptor antagonist possessing some anti-inflammatory effects although the molecular mechanism of these anti-inflammatory effects is unknown. In this study, we aimed to investigate the effect of montelukast on nuclear factor (NF)-kappaB-associated histone acetylation activity in phorbol myristate acetate (PMA)-differentiated U937 cells.

METHODS

We examined the inhibitory effects of montelukast on TNF-alpha-induced IL-8 production in PMA-differentiated U-937 cells. U-937 cells were exposed to PMA (50 ng/mL) for 48 h to allow differentiation to macrophages. Macrophages were then exposed to TNF-alpha (10 ng/mL) in the presence or absence of montelukast (0.01-10 microm) for 24 h. After this time, the concentration of IL-8 in the culture supernatant was measured by sandwich-type ELISA kit. The effect of signalling pathways on TNF-alpha-induced IL-8 release was examined pharmacologically using selective NF-kappaB/IKK2 (AS602868, 3 microm), (PD98059, 10 microm) and p38 mitogen activated protein kinase (MAPK) (SB203580, 1 microm) inhibitors. NF-kappaB DNA binding activity was measured by a DNA-binding ELISA-based assay. NF-kappaB-p65-associated histone acetyltransferase (HAT) activity was measured by immunoprecipitation linked to commercial fluorescent HAT.

RESULTS

TNF-alpha-induced IL-8 release was suppressed by an NF-kappaB inhibitor but not by MEK or p38 MAPK inhibitors. Montelukast induced a concentration-dependent inhibition of TNF-alpha-induced IL-8 release and mRNA expression that reached a plateau at 0.1 microm without affecting cell viability. Montelukast did not affect NF-kappaB p65 activation as measured by DNA binding but suppressed NF-kappaB p65-associated HAT activity.

CONCLUSION

Montelukast inhibits TNF-alpha-stimulated IL-8 expression through changes in NF-kappaB p65-associated HAT activity. Drugs targeting these enzymes may enhance the anti-inflammatory actions of montelukast.

A randomized open-label comparative study of montelukast versus theophylline added to inhaled corticosteroid in asthmatic children

BACKGROUND

Inhaled corticosteroids (ICSs) are widely used in combination with other classes of drugs for treatment of childhood asthma. The efficacy and the safety of montelukast added to low-dose ICS therapy were compared with those of sustained-release theophylline added to low-dose ICS therapy in asthmatic children in the present study.

METHODS

Following the 2-week run-in period, 6-to 14-year old patients receiving treatment with ICSs were randomized to treatment for 4 weeks with either montelukast 5 mg once daily or sustained release theophylline 5-8 mg/kg (dry syrup) or 100-200 mg (tablet) twice daily. Patients also received a fixed dose of ICS throughout the run-in and treatment periods. The primary efficacy endpoint was the change from baseline in peak expiratory flow (PEF) at Week 2.

RESULTS

A significant increase in morning PEF was observed in the add-on montelukast group as compared with the add-on theophylline group at Week 2 (change from baseline of 22.8 L/minvs. 8.7 L/min; p = 0.041 for between-group difference) and at Week 4 (31.0 L/minvs. 9.8 L/min; p = 0.012). A significant increase in evening PEF was observed in the add-on montelukast group as compared with the add-on theophylline group at Week 4 (24.7 L/minvs. 8.7 L/min; p = 0.027). There were no significant differences between the treatment groups in incidences of clinical and laboratory adverse experiences.

CONCLUSIONS

The results indicate that montelukast added to low-dose ICS is an effective and safe option for the treatment of asthma in children.

Montelukast in pediatric asthma management

Leukotriene modifiers (receptor antagonist and biosynthesis inhibitor) represent the first mediator specific therapeutic option for asthma. Montelukast, a leukotriene receptor antagonist is the only such agent approved for use in pediatric patients. Montelukast modifies action of leukotrienes, which are the most potent bronchoconstrictors, by blocking Cysteinyl leukotriene receptors. Systemic drug like mountelukast can reach lower airways and improves the peripheral functions which play a crucial role in the evolution of asthma. Review of existing literature showed that montelukast compared to placebo has proven clinical efficacy in better control of day time asthma symptoms, percentage of symptom free days, need for rescue drugs and improvement in FEV 1. Studies also demonstrated improvement in airway inflammation as indicated by reduction in fractional exhaled nitric oxide, a marker of inflammation. Studies comparing low dose inhaled corticosteroids (ICS) with montelukast are limited in children and conclude that it is not superior to ICS. For moderate to severe persistent asthma, montelukast has been compared with long acting beta agonists (LABA) as an add-on therapy to ICS, montelukast was less efficacious and less cost-effective. It has beneficial effects in exercise induced asthma and aspirin-sensitive asthma. Montelukast has onset of action within one hour. Patient satisfaction and compliance was better with montelukast than inhaled anti-inflammatory agents due to oral, once a day administration. The recommended doses of montelukast in asthma are- children 1-5 years: 4 mg chewable tablet, children 6-14 years: 5mg chewable tablet,

ADULTS

10mg tablet; administered once daily. The drug is well tolerated. Based on the presently available data montelukast may be an alternative treatment for mild persistent asthma as monotherapy where ICS cannot be administered. It is also an alternative to LABA as an add-on therapy to ICS for moderate to severe persistent asthma. The other indications for use of montelukast include: allergic rhinitis, exercise induced bronchoconstriction and aspirin-induced asthma.

Effect of montelukast on exhaled leukotrienes and quality of life in asthmatic patients

STUDY OBJECTIVES

In some patients with asthma treated with inhaled corticosteroids, suppression of inflammation is incomplete. This may be because the effect of corticosteroids on cysteinyl-leukotriene (cys-LT) biosynthesis is limited. Montelukast is a cys-LT antagonist that significantly improves asthma control in corticosteroid-treated asthmatic patients. However, not all patients treated with cys-LT antagonists show a clinical improvement.

DESIGN

We have studied the effect of treatment for 4 weeks with montelukast (10 mg/d) on exhaled cys-LTs and leukotriene B4 (LTB4), exhaled nitric oxide, asthma quality of life (AQL), and respiratory function in patients with stable asthma.

SETTING

Asthma clinics in general practice.

PATIENTS

We studied 50 patients (30 men; mean +/- SEM age, 53 +/- 2 years) who were treated with inhaled corticosteroids.

MEASUREMENTS AND RESULTS

We detected cys-LTs in exhaled breath condensate in 25 of 50 patients; however, in the normal nonasthmatic subjects, cys-LTs were below the limit of detection. After treatment with montelukast, there was a fall in cys-LT concentrations from 14.6 +/- 3.3 to 8.5 +/- 2.6 pg/mL after 2 weeks (p > 0.05) and to 3.9 +/- 1.3 pg/mL after 4 weeks (p < 0.01). Exhaled LTB4 levels were also elevated. After treatment with montelukast, LTB4 levels fell from 33.0 +/- 3.9 to 20.4 +/- 2.5 pg/mL after 2 weeks of treatment (p < 0.05), and to 17.0 +/- 2.2 pg/mL after 4 weeks of treatment (p < 0.01). These changes in exhaled cys-LT and LTB4 were associated with significant improvements in AQL scores.

CONCLUSIONS

It appears that in some patients with stable asthma treated with inhaled corticosteroids, the suppression of inflammation is incomplete. Adding a leukotriene receptor antagonist can provide a complementary effect of controlling inflammation, with a significant improvement in quality of life.

Exhaled nitric oxide in the assessment of asthma

PURPOSE

Asthma is now defined as a TH2-mediated inflammatory disease involving both large and small airways. However, assessment of airways inflammation is limited by techniques that are time consuming and possibly distressing to the patient. Exhaled nitric oxide, an easily and rapidly obtained noninvasive study, is a potential surrogate for measuring airways inflammation, but its clinical utility remains to be determined. This review examines the role of exhaled nitric oxide in assessing and directing therapy of asthmatic airways inflammation.

RECENT FINDINGS

It is well established that exhaled nitric oxide is increased in patients with untreated asthma and decreases with corticosteroid treatment. Exhaled nitric oxide also generally correlates with eosinophilic inflammation in asthmatic patients. Recent studies show that this correlation is especially pronounced in atopic subjects with asthma when compared with nonatopic subgroups. Recent studies also show that exhaled nitric oxide may be useful in identifying subclinical inflammation, assessing the antiinflammatory effects of asthma medications other than inhaled or oral corticosteroids, and heralding an asthma exacerbation. A number of new studies assert the utility of exhaled nitric oxide as a diagnostic tool for asthma.

SUMMARY

Exhaled nitric oxide may be a useful parameter for monitoring asthmatic inflammation, adjusting therapy, and diagnosing asthma, although prospective longitudinal trials investigating the correlation between exhaled nitric oxide and clinical outcomes are necessary to determine its utility.