Difficult asthma or Churg-Strauss syndrome?

Identifying relevant determinants of in-hospital time to diagnosis for ANCA-associated vasculitis patients

Objectives

Diagnosing patients with ANCA-associated vasculitis (AAV) can be challenging owing to its rarity and complexity. Diagnostic delay can have severe consequences, such as chronic organ damage or even death. Given that few studies have addressed diagnostic pathways to identify opportunities to improve, we performed a clinical audit to evaluate the diagnostic phase.

Methods

This retrospective, observational study of electronic medical records data in hospitals focused on diagnostic procedures during the first assessment until diagnosis.

Results

We included 230 AAV patients from nine hospitals. First assessments were mainly performed by a specialist in internal medicine (52%), pulmonology (14%), ENT (13%) or rheumatology (10%). The overall median time to diagnosis was 13 [interquartile range: 2–49] days, and in patients primarily examined by a specialist in internal medicine it was 6 [1–25] days, rheumatology 14 [4–45] days, pulmonology 15 [5–70] days and ENT 57 [16–176] days (P = 0.004). Twenty-two of 31 (71%) patients primarily assessed by a specialist in ENT had non-generalized disease, of whom 14 (64%) had ENT-limited activity. Two hundred and nineteen biopsies were performed in 187 patients (81%). Histopathological support for AAV was observed in 86% of kidney biopsies, 64% of lung biopsies and 34% of ENT biopsies.

Conclusion

In The Netherlands, AAV is diagnosed and managed predominantly by internal medicine specialists. Diagnostic delay was associated with non-generalized disease and ENT involvement at presentation. Additionally, ENT biopsies had a low diagnostic yield, in contrast to kidney and lung biopsies. Awareness of this should lead to more frequent consideration of AAV and early referral for a multidisciplinary approach when AAV is suspected.

Differential Diagnosis of Asthma

Asthma is one of the most common chronic syndromes worldwide (Moorman et al., Vital Health Stat 3(35), 2012). It is not a diagnosis but a clinical syndrome based on a constellation of signs and symptoms (Li et al., Ann Allergy Asthma Immunol 81:415–420(IIa), 1998). The classic symptoms of asthma include chest tightness, wheeze, cough, and dyspnea (Moorman et al., Vital Health Stat 3(35), 2012). The term asthma encompasses a spectrum of pulmonary diseases sharing the hallmark of reversible airway obstruction and can be classified as allergic or non-allergic (Löwhagen, J Asthma. 52(6):538–44, 2015). Asthma designated allergic is due to an immunoglobulin E (IgE)-mediated process, but as noted not all asthma is allergic in etiology (Romanet-Manent et al., Allergy 57:607–13, 2002). The differential diagnosis for asthma is broad and requires a detailed history with supportive pulmonary function tests to be properly diagnosed.

Safety of omalizumab in asthma

INTRODUCTION

Omalizumab is the first mAb to be introduced for the management of asthma. It is also the first agent designed to block the effects of IgE in initiating the allergic cascade resulting in asthma manifestations. Introduced in 2003, it is now widely used as an effective therapeutic tool in moderate-to-severe allergic asthmatics who are uncontrolled on maximal conventional therapy, including high-dose inhaled steroids and long-acting β-agonists. There is still understandable concern regarding the long-term effects of this drug.

AREAS COVERED

The authors provide a review of safety data generated by controlled clinical trials and post-marketing surveillance as well as a brief overview of the clinical indications and efficacy of omalizumab. They also address specific issues of concern, including the risk of anaphylaxis and malignancy. The reader will gain a working knowledge of the role of omalizumab in current guidelines for the management of asthma.

EXPERT OPINION

Omalizumab appears to be safe and well-tolerated. The possible association of malignancy with omalizumab has been of the greatest concern to patients and physicians. Analysis of clinical study data shows that this incidence is rare and the relative risk of cancer with omalizumab is not significantly different from that which is expected in the general population of people with asthma. As part of a relatively new class of agents, continued surveillance is needed as its indications expand and its use in the population continues to grow.

[Difficult asthma]

Difficult asthma is a major issue in pulmonary medicine today because of its cost for patients and society. Difficult asthma is asthma that remains uncontrolled despite optimal specialist management. The validity of the diagnosis must be reconsidered in these cases: associated or differential diagnoses may be involved in the lack of control, and it is always necessary to assess the patient's treatment adhesion. Sufficient time--at least a year--must be taken to get to know the patient and to meet the objectives set. The standard asthma therapies should be tested objectively. Severe asthma is the reality of difficult asthma that endures despite a reaffirmed diagnosis, optimal compliance and controlled comorbidities. Better knowledge is needed of the pathophysiology of these patients' asthma. Improved knowledge of these phenotypes will make it possible to develop innovative treatments. They will need to be validated in clinical research for subsequent use that is wider but more rational because targeted at phenotypes likely to benefit from them.

The Churg Strauss syndrome (allergic granulomatous angiitis): review and update

OBJECTIVES

Review the clinical and physiopathologic aspects of the Churg-Strauss syndrome (CSS), including recent data regarding treatment and possible etiologic and triggering factors.

METHODS

A search of the Medline database was conducted between 1966 and 2002, regarding CSS and related vasculitic conditions. Original articles were reviewed as well as major vasculitis textbooks, which were also examined for original references.

RESULTS

CSS has been increasingly recognized during the past few decades, but remains an uncommon disease of unknown cause. The disorder had been traditionally classified as a variant of polyarteritis nodosa until its updated description by Churg and Strauss in 1951. Although it shares various clinical laboratory and pathologic characteristics with polyarteritis nodosa and Wegener granulomatosis, a distinct combination of features makes it a separate entity. The presence of asthma, usually of adult onset, along with other allergic symptoms, peripheral and tissue eosinophilia, and systemic vasculitis should prompt the clinician to consider the diagnosis, seek potential confirmation with a tissue biopsy, and begin therapy to minimize complications and prevent permanent organ damage. The treatment of CSS has been mainly extrapolated from other vasculitides, and the literature addressing drug therapy for this specific syndrome is limited.

CONCLUSIONS

CSS is a distinct entity that should be recognized and distinguished from other forms of vasculitis to provide the appropriate early treatment, which could prevent permanent organ damage.

Refractory asthma

Treating patients with refractory asthma remains an ongoing challenge. Although most patients respond to large doses of systemic corticosteroid, the adverse effects associated with such a treatment limit its general use. Clinicians treating patients with refractory asthma must consider tapering systemic corticosteroid at every opportunity. Recent advances in the understanding of the pathogenesis of refractory asthma and corticosteroid resistance have fueled further study in the mechanisms of these processes and have prompted consideration of new treatment approaches. Unfortunately, most alternative approaches require more rigorous evidence to support their regular use.

Montelukast: a review of its therapeutic potential in asthma in children 2 to 14 years of age

Montelukast is a cysteinyl leukotriene receptor antagonist which is used as a preventive treatment for persistent asthma in patients > or =2 years of age. In children aged 6 to 14 years montelukast (5 mg/day) treatment resulted in a significant increase in FEV(1) (forced expiratory volume in 1 second, primary clinical outcome) during an 8-week randomized, double-blind trial. Moreover, significant improvements were observed for a range of secondary endpoints assessing symptoms, exacerbation rates, beta-agonist usage and quality of life. Concomitant administration of montelukast (5 mg/day) and inhaled budesonide (200 microg twice daily) resulted in a trend towards an increase in FEV(1) (p = 0.06, primary endpoint) and a statistically significant reduction in both as-needed beta(2)-agonist usage and the percentage of days with asthma exacerbations compared with budesonide plus placebo. No significant differences were observed in asthma-related quality of life between the two groups. During clinical trials both improvements in lung function and reductions in as-needed beta(2)-agonist usage were generally observed within 1 day after initiation of therapy in children 2 to 14 years of age with persistent asthma. Data from a randomized, nonblind trial in 6- to 11-year-old children and a 6-month extension to this trial suggest that both compliance to therapy and patient satisfaction are greater for montelukast than for either inhaled sodium cromoglycate or inhaled beclomethasone. In addition, patients and parents preferred oral montelukast over sodium cromoglycate. In 2- to 5-year-old children with persistent asthma, montelukast (4 mg/day) treatment resulted in significant improvements in a range of outcomes, such as as-needed beta(2)-agonist usage, symptom scores and percentage of days with asthma symptoms, as assessed during a randomized, double-blind trial primarily designed to assess tolerability. Data from small randomized, double-blind trials suggest that montelukast reduces exercise-induced bronchoconstriction in 6- to 14-year-old children. Montelukast is generally well tolerated. The frequency of adverse events in montelukast-treated children of all ages was comparable to that in patients receiving placebo.

CONCLUSION

Oral montelukast has shown efficacy as a preventive treatment for asthma during clinical trials in children aged 2 to 14 years. The drug offers benefits over more standard therapies such as inhaled sodium cromoglycate and nedocromil in terms of compliance and convenience. In addition, the drug offers significant benefits when added to inhaled corticosteroids (according to secondary endpoints). Montelukast offers an effective, well tolerated and convenient treatment option for children with asthma.

Experience of 10 years with Churg-Strauss syndrome: An accompaniment to or a transition from aspirin-induced asthma?

Churg-Strauss syndrome is a rare, idiopathic, eosinophilic vasculitis appearing in concurrence with asthma which is often severe. Aspirin-induced asthma is a special clinical syndrome existing in nearly 10 % of adult asthmatics. After leukotriene antagonists had been marketed there has been marked increase in Churg-Strauss syndrome reports among the patients who had been followed up with asthma. This syndrome seems to be more frequent among the patients with aspirin-induced asthma. The role of leukotriene antagonists on the conversion from aspirin-induced asthma to Churg-Strauss syndrome has aroused attention and been questioned. Here we report 7 cases of Churg-Strauss syndrome where three had aspirin induced asthma which we have diagnosed in the last 10 years and where only one of them seems to be related to antileukotriene drug use.

Consensus guidelines for asthma therapy

OBJECTIVE

This article provides information on the consensus reached by the Antileukotriene Working Group on the role of leukotriene (LT) modifiers in the treatment of asthma.

DATA SOURCES

Relevant and appropriate controlled clinical studies were used. Only literature in the English language was reviewed.

STUDY SELECTION

Material was taken from academic/scholarly journals and appropriate reviews.

RESULTS

Only limited use of LT-modifying agents has been recommended in recently published guidelines of the National Asthma Education and Prevention Program and the National Heart, Lung, and Blood Institute. Consequently, the Antileukotriene Working Group was convened to arrive at a consensus on the wider use of LT modifiers in the treatment of asthma. The group' s purpose was 2-fold: to review and disseminate information on the role of LT modifiers in clinical practice. As determined by the group, a thorough understanding of the patient's disease, patient education, and an effective patient-clinician relationship are key elements in overall patient management.

CONCLUSIONS

Based on evidence from clinical trials and expert opinions of participants comprising the Antileukotriene Working Group, LT-modifying agents potentially may be used as first-line therapy, in combination regimens, and as an alternative to inhaled corticosteroids in the treatment of asthma.

Zafirlukast: an update of its pharmacology and therapeutic efficacy in asthma

Zafirlukast is a selective and competitive orally administered inhibitor of the cysteinyl leukotrienes LTC4, LTD4 and LTE4. The drug is indicated for the prophylaxis and treatment of chronic asthma, and has been developed in response to mounting evidence indicating the importance of the cysteinyl leukotrienes in the pathogenesis of this disorder. The efficacy of zafirlukast 20 mg twice daily has been shown in double-blind placebo-controlled studies of up to 13 weeks' duration in patients aged > or = 12 years. Zafirlukast was consistently superior to placebo in improving objective measures of lung function and subjective measures such as symptom scores and use of as-required bronchodilator therapy. This dosage is also as effective when added to low-dosage inhaled corticosteroid therapy as doubling of corticosteroid dosages. Recent studies indicate superior efficacy over zafirlukast of twice-daily inhaled fluticasone propionate 88 microg or salmeterol 42 microg, although zafirlukast was nevertheless associated with clinical improvement. Data also show zafirlukast 40 mg to be of similar efficacy to pranlukast 225 mg (both twice daily). Overall, preliminary pharmacoeconomic data suggest that healthcare costs are reduced by zafirlukast therapy, although superior cost effectiveness has been reported with inhaled fluticasone propionate. and further studies are needed. Data are available to show improvements in patient-rated quality of life, and preference for and high rates of compliance with zafirlukast. In clinical trials, zafirlukast has shown an adverse event profile similar to that of placebo. Isolated reports of hepatic dysfunction in a small number of individuals receiving the drug have been received, and recommendations for monitoring of patients are in place. Although no causal relationship has been established between zafirlukast and Churg-Strauss Syndrome, patients undergoing corticosteroid dosage reductions require careful surveillance.

CONCLUSIONS

zafirlukast is an effective and well tolerated agent for preventive monotherapy in mild to moderate persistent asthma. Emerging data indicate benefit of the drug when added to low-dosage inhaled corticosteroids and show that it may be a viable alternative to inhaled adjunctive treatments and increased corticosteroid dosages in some patients. Although inhaled fluticasone propionate and salmeterol have been associated with greater clinical improvement than zafirlukast in clinical studies, compliance considerations and the confirmed clinical efficacy relative to placebo of the drug denote zafirlukast as an effective alternative in treatment programmes based on individualised therapy. As experience with zafirlukast accumulates, it is expected that the drug will be positioned more definitively in national and international treatment guidelines.

Regulation of leukotrienes in the management of asthma: biology and clinical therapy

Leukotrienes (LTs) are the ultimate synthetic product resulting from the intracellular hydrolysis of membrane phospholipid at the nuclear envelope in inflammatory cells. Activated cytosolic phospholipase (cPLA2) catalyzes the production of arachidonic acid, which is converted by cyclooxygenases into leukotriene A4 (LTA4) and subsequently into the chemotaxin LTB4, which has no direct bronchoconstrictor activity. In certain inflammatory cells, LTA4 is converted into the cysteinyl leukotriene (cysLT) LTC4, which is converted into LTD4 and finally to LTE4 after extracellular transport. All cysLTs occupy the same receptors and are extremely potent bronchoconstricting agents that are pathogenetic in both asthma and allergy. With the identification of the structure of the cysLT receptor, antileukotriene therapies have been developed that either (a) inhibit synthesis of leukotriene (through 5-lipoxygenase inhibition) or (b) block the cysLT receptor. Preliminary investigations indicate that corticosteroids also may partially block the synthesis of cysLT and that cysLTs may be chemotactic for other inflammatory cells, e.g. eosinophils, by a mechanism that has not yet been defined. Currently, anti-LT therapies are approved by the US Food and Drug Administration (FDA) only for patients with asthma. These drugs generally are moderately efficacious agents, although they are highly efficacious in aspirin-induced asthma (AIA). In other forms of asthma, inhaled corticosteroid (ICS) therapy has been more effective than anti-LT therapy in improving air flow obstruction. However, anti-LT agents are additive to beta-adrenoceptor and ICS in their effects. Accordingly, anti-LT therapies are used frequently as supplemental treatments in asthmatic patients whose asthma is not optimally controlled by a combination of other drugs, including long-acting beta-adrenoceptor drugs and ICS agents. The growth of leukotriene receptor antagonists (LTRAs) has been extraordinary in the United States. The exceptional safety of these agents and their ease of administration as tablets taken once or twice daily has spurred this growth. In the past year, the high-affinity cysLT receptor has been cloned. This holds forth the promise of a second generation of LTRA agents of even greater efficacy and possibly greater duration of action.

Clinical safety and tolerability of montelukast, a leukotriene receptor antagonist, in controlled clinical trials in patients aged > or = 6 years

OBJECTIVE

Montelukast is a leukotriene receptor antagonist administered orally once daily for treatment of chronic asthma in adults and children. A comprehensive analysis of safety data from double-blind, randomized, placebo-controlled trials with montelukast has not been previously reported.

PATIENTS AND METHODS

A pooled analysis of safety data from 11 multicentre, randomized, controlled montelukast Phase IIb and III trials and five long-term extension studies was performed. A total of 3386 adult patients (aged 15-85 years) and 336 paediatric patients (aged 6-14 years) were enrolled in the trials; 2031 adults received montelukast for up to 4.1 years, and 257 children received montelukast for up to 1.8 years. Summary statistics comparing incidences of adverse events among treatment groups were calculated.

RESULTS

The overall incidence of clinical and laboratory adverse events among montelukast-treated patients, both adult and paediatric, was similar to that among patients receiving placebo. There were no clinically relevant differences in individual adverse events, including infectious upper respiratory conditions and transaminase elevations, between montelukast and placebo groups. Discontinuations due to adverse events occurred with similar frequencies during placebo, montelukast and inhaled beclomethasone therapy. No dose-related adverse effects of montelukast were observed in adults treated with dosages as high as 200 mg per day (20 times the recommended dose) for 5 months. This tolerability profile montelukast observed in clinical trials has been generally reflected in the post-marketing safety experience seen to date.

CONCLUSIONS

These data indicate a tolerability profile for montelukast similar to placebo during both short-term and long-term administration, even at doses substantially higher than the recommended clinical dose of 10 mg once daily for adults and 5 mg once daily for children aged 6-14 years.

Leukotriene receptor antagonist therapy

Leukotriene receptor antagonists (LTRA) are a new class of drugs for asthma treatment, available in tablet form. Their unique mechanism of action results in a combination of both bronchodilator and anti-inflammatory effects. While their optimal place in asthma management is still under review, LTRA represent an important advance in asthma pharmacotherapy.

State of the art: therapeutic controversies in severe acute asthma

This is a transcript of the 1999 SAEM State-of-the-Art session on "Therapeutic Controversies in Severe Acute Asthma," presented at the 1999 SAEM annual meeting in Boston. The aim of this session was to address some of the current controversies in the management of acute asthma exacerbations, a major issue in emergency medicine. Despite many recent advances in asthma management, morbidity and mortality remain high. While many of us have strong feelings on how asthma patients should be treated, many of our assertions are not based on good science, and there are numerous areas of controversy. This discussion focuses on the controversy over beta agonist treatment for acute asthma, the physiology of corticosteroids in asthma, and the emergency use of leukotriene-modifying agents.

Montelukast: a review of its therapeutic potential in persistent asthma

Montelukast is a cysteinyl leukotriene receptor antagonist used to treat persistent asthma in patients aged > or = 6 years. The drug has a rapid onset of action. Improvements in lung function and reductions in as-needed beta2-agonist usage are apparent within 1 day of initiating montelukast treatment in adults and adolescents (aged > or = 15 years treated with 10 mg/day) or children (aged 6 to 14 years treated with 5 mg/day) with persistent asthma as shown in clinical trials. In two 12-week, multicentre, randomised, double-blind studies in adults and adolescents aged > or = 15 years with persistent asthma [forced expiratory volume in 1 second (FEV1) = 50 to 85% predicted] there was significantly (p < 0.05) greater improvement in FEV1, symptom scores, peak expiratory flow (PEF), as-needed beta2-agonist use, peripheral eosinophil counts and health-related quality of life (QOL) in patients treated with montelukast 10 mg/day than in recipients of placebo. Improvements were significantly greater in patients treated with inhaled beclomethasone 400 microg/day than in recipients of montelukast 10 mg/day in 1 of these studies. Nonetheless, 42% of montelukast recipients experienced > or = 11% improvement in FEV1, the median improvement in this parameter in beclomethasone-treated patients. In an 8-week multicentre, randomised, double-blind, study in children aged 6 to 14 years with persistent asthma (FEV1 50 to 85% predicted), montelukast 5 mg/day produced significantly greater improvements in FEV1, clinic PEF, as-needed beta2-agonist use, peripheral eosinophil counts, asthma exacerbations and QOL scores than placebo. The combination of montelukast 10 mg/day plus inhaled beclomethasone 200 microg twice daily provided significantly better asthma control than inhaled beclomethasone 200 microg twice daily in adults with poorly controlled asthma (mean FEV1 = 72% predicted) despite 4 weeks treatment with inhaled beclomethasone. Patients receiving the combination experienced significant improvements in FEV1 and morning PEF, significant reductions in daytime symptom scores, as-needed beta2 agonist usage and night-time awakenings with asthma, and had significantly lower peripheral blood eosinophil counts after 16 weeks in this multicentre, randomised, double-blind, placebo-controlled study. Among adults (FEV1 > or = 70%) treated with montelukast 10 mg/day for 12 weeks, inhaled corticosteroid dosages were titrated downward by 47% (vs 30% in placebo recipients), 40% of patients were tapered off of inhaled corticosteroids (vs 29%), and significantly fewer patients (16 vs 30%) experienced failed corticosteroid rescues in a multicentre, randomised, double-blind study. During clinical studies, the frequency of adverse events in montelukast-treated adults, adolescents and children was similar to that in placebo recipients. In conclusion, montelukast is well tolerated and effective in adults and children aged > or = 6 years with persistent asthma including those with exercise-induced bronchoconstriction and/or aspirin sensitivity. Furthermore, montelukast has glucocorticoid sparing properties. Hence, montelukast, as monotherapy in patients with mild persistent asthma, or as an adjunct to inhaled corticosteroids is useful across a broad spectrum of patients with persistent asthma.

Asthma medications: basic pharmacology and use in the athlete

OBJECTIVE

Asthma is a chronic disease that affects athletes at all levels of sport. Several categories of drugs, including relatively new agents, are available to treat the asthmatic patient. By understanding the appropriate uses and effects of these drugs, the athletic trainer can assist the asthmatic athlete in improving therapeutic outcomes from the asthma therapy. The appropriate use of these medications includes not only the use of the appropriate drug(s), but also appropriate technique for administration, compliance with the prescribed dosing intervals, and sufficient care to avoid side effects.

DATA SOURCES

I searched MEDLINE and CINAHL from 1982 to 1999 and International Pharmaceutical Abstracts from 1990 to 1999. Terms searched were "asthma," "athlete,""athletic," "exercise-induced," "exercise," "performance," "therapy," and "treatment."

DATA SYNTHESIS

Bronchodilators include beta2 agonists, anticholinergics, and methylxanthines. Of these, the beta2 agonists used by inhalation are the drugs of choice to treat an acute asthma attack or to prevent an anticipated attack (such as before exercise). Anti-inflammatory agents include corticosteroids mast cell-stabilizing agents, and antileukotrienes. Corticosteroids by inhalation are the drugs of choice for long-term treatment to curb the inflammatory process in the lung. Each of these drug categories has a unique mechanism of action. The athletic trainer who understands the appropriate use of these medications can help the athlete to obtain optimal results from drug therapy. Encouraging the athlete to comply with appropriate therapy, monitoring the effectiveness of the therapy, and recognizing the stimuli that initiate asthmatic attacks can improve the patient's therapeutic outcomes.

CONCLUSIONS/RECOMMENDATIONS

The athletic trainer has an opportunity to play a key role in ensuring that the asthmatic athlete achieves the desired outcomes from treatment. The athletic trainer can help to minimize the effect of asthma on athletic performance by ensuring that the athlete uses inhaler devices properly, is compliant with the prescribed drug therapy, monitors pulmonary function appropriately, uses medications properly before exercise, and is aware of the factors that initiate asthma symptoms.

Autoimmune diseases associated with drugs, chemicals and environmental factors

Autoimmune connective tissue diseases are complex multisystems and may be life threatening. Their aetiology is unknown but genetic, hormonal and environmental factors are important. In systemic lupus erythematosus (SLE), factors such as UV light and drugs, including oestrogen, may trigger the disease; silica exposure may also be important. Scleroderma is associated with silica exposure and drugs such as bleomycin and pentazocine may induce scleroderma-like diseases. Organic solvents such as vinyl chloride and epoxy resins may also be associated with scleroderma-like illnesses. The toxic oil syndrome and eosinophila-myalgia syndrome are best known examples of connective tissue diseases induced by chemical exposure. The systemic vasculitides and in particular cutaneous vasculitis may be induced by drugs and possibly environmental factors. A number of autoimmune connective tissue diseases may therefore be associated with exposure to drugs, chemicals and environmental factors and the risks associated with these should be minimised where possible.

Montelukast. No current use for asthma

Montelukast (Singulair), an antiasthma drug belonging to the leukotriene antagonist family, has two indications: as adjunctive treatment for mild-to-moderate chronic asthma when regular inhaled steroid therapy and short-acting inhaled beta2 stimulants "on demand" are inadequate; and in prevention of effort-induced asthma. The clinical file on montelukast contains no methodologically acceptable comparisons with reference treatments. Several placebo-controlled trials have shown the efficacy of montelukast, with improvement in clinical scores and respiratory function tests in those with chronic asthma and prevention of effort-induced asthma. For chronic asthma, montelukast has not been compared with oral or inhaled long-acting beta2 stimulants or with sustained-release theophylline in patients inadequately controlled by steroid therapy. For effort-induced asthma, only two trials have compared montelukast with salmeterol. On the basis of preliminary results, the authors of both studies concluded that montelukast was superior. Clinical trials showed no clear difference in the frequency of side effects in patients taking montelukast and patients taking placebo. Montelukast, however, might be associated with Churg-Strauss syndrome in rare cases. Montelukast is expensive.

Leukotriene modifiers and Churg-Strauss syndrome: adverse effect or response to corticosteroid withdrawal?

Zafirlukast, montelukast and pranlukast are all cysteinyl leukotriene receptor antagonists that have recently been approved for the treatment of asthma. Within 6 months of zafirlukast being made available on the market, 8 patients who received the agent for moderate to severe asthma developed eosinophilia, pulmonary infiltrates, cardiomyopathy and other signs of vasculitis; the syndrome that these patients developed was characteristic of the Churg-Strauss syndrome. All of the patients had discontinued systemic corticosteroid use within 3 months of presentation and all developed the syndrome within 4 months of zafirlukast initiation. The syndrome dramatically improved in each patient upon reinitiation of corticosteroid therapy. Since the initial report, there have been multiple similar cases reported to the relevant pharmaceutical companies and to federal drug regulatory agencies in association with zafirlukast as well as with pranlukast, montelukast, and with use of high doses of inhaled corticosteroids, thus leading to an increased incidence rate of the Churg-Strauss syndrome. Many potential mechanisms for the association between these drugs and the Churg-Strauss syndrome have been postulated including: increased syndrome reporting due to bias; potential for allergic drug reaction; and leukotriene imbalance resulting from leukotriene receptor blockade. However, careful analysis of all reported cases suggests that the Churg-Strauss syndrome develops primarily in those patients taking these asthma medications who had an underlying eosinophilic disorder that was being masked by corticosteroid treatment and unmasked by novel asthma medication-mediated corticosteroid withdrawal, similar to the forme fruste of the Churg-Strauss syndrome. It remains unclear what the exact mechanism for this syndrome is and whether this represents an absolute increase in cases of vasculitis, but it appears that none of the asthma medications implicated in leading to the development of Churg-Strauss syndrome was directly causative of the syndrome. These agents remain well tolerated and effective medications for the treatment of asthma, although physicians must be wary for the signs and symptoms of the Churg-Strauss syndrome, particularly in patients with moderate to severe asthma in whom corticosteroids are tapered.