Leukotrienes and the mechanism by which the LTRAs block their asthma-related effects

The past several decades of research have culminated in the recognition of asthma as a chronic inflammatory disease of the airways and the knowledge that cysteinyl leukotrienes (CysLTs) are important mediators in the inflammatory process. These potent bronchoconstrictors inhibit mucociliary transport while stimulating mucus secretion, thereby contributing to airway obstruction. They also increase microvascular permeability, which results in airway edema; recruit inflammatory cells; and increase expression of proinflammatory cytokines. CysLTs produce these asthma-related effects by interacting with the CysLT1 receptor. Thus, the leukotriene receptor antagonists (LTRAs) were specifically developed as antiasthma agents that provide controller effects by blocking this receptor. The 2 LTRAs available for clinical use in the United States--montelukast and zafirlukast--are potent inhibitors of leukotriene D4 binding to the CysLT1 receptor.

Safety of antileukotriene agents in asthma management

OBJECTIVE

This article presents information on the safety of zafirlukast, montelukast, and zileuton, three antileukotrienes (anti-LTs) approved in the United States for the prophylaxis and treatment of asthma. After reading this article, readers should have an understanding both of the general safety of anti-LTs and their specific adverse effects.

DATA SOURCES

Relevant and appropriate controlled clinical studies on the safety of anti-LTs in asthma were used. Only literature in the English language was reviewed.

STUDY SELECTION

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

RESULTS

Antiasthma agents, including corticosteroids, beta2-agonists, and methylxanthines, may be categorized into two classes: those used for the long-term control and prevention of persistent asthma and those used for the prompt relief of acute symptoms and exacerbations of the disease. Although most agents are safe and well tolerated when used properly, adverse effects may occur with use at higher dose levels. The anti-LTs, including zafirlukast, montelukast, and zileuton, are the first new pharmacologic class in the therapeutic armamentarium for asthma management to be approved in the United States in the past 20 years. Both zafirlukast and montelukast carry pregnancy category B classification whereas zileuton carries pregnancy category C classification. The most common adverse effects observed in clinical trials were headache, pharyngitis, abdominal pain, dyspepsia, and cough.

CONCLUSIONS

The results of clinical trials and real-world experience indicate that these agents are generally safe and well tolerated, with an incidence of adverse effects comparable with placebo.

Diagnostic testing in occupational asthma

BACKGROUND

Occupational asthma may often be a challenge to diagnose as the relationship between work and symptoms may not be immediately clear. The potential consequences for the worker's career make an accurate diagnosis essential. A history of work-associated asthma symptoms that recede when the patient is not at work is the first clue.

METHODS

A nonspecific bronchial challenge, most commonly with methacholine, can help confirm the diagnosis of asthma. Specific IgE to suspected agents can be tested for, preferably with skin testing. Serial monitoring of peak expiratory flow rate (PEFR) or forced expiratory volume in 1 second (FEV1) at work and outside of work can determine if the asthma is occupational in nature.

CONCLUSION

Specific bronchial challenge to suspected occupational agents is the gold standard for diagnosis of occupational asthma.

Allergic inflammation in upper and lower airways

OBJECTIVE

The primary reason for this review is to discuss the relationship between upper and lower airways at various levels with the emphasis on common pathophysiologic mechanisms, and how treatment of the upper airways will benefit the lower airways.

DATA SOURCES

The main source of information is derived from original articles and books, with an extensive bibliography included.

STUDY SELECTION

Studies were derived almost exclusively from articles and reviews in peer-reviewed journals.

RESULTS

The prevalence of rhinitis and asthma are both increasing. Common to both the upper and lower airways are the triggers, many of the inflammatory cells and mediators, and the treatment modalities. By contrast, there are organ-specific differences in the reaction to various stimuli in the nose or lung, with each organ manifesting its own vocabulary of response.

CONCLUSIONS

There are meaningful relationships between upper and lower airways at various levels of our understanding. Differential responses to medications help us better understand pathogenic mechanisms in rhinitis and asthma. Further, treatment of the upper airways provides additional benefit to the lower airways.

Efficacy of anti-LT agents in the treatment of chronic asthma

Anti-LT agents are the first new class of asthma medication to be approved in the last 20 yr. Current asthma treatment guidelines recommend antileukobriene agents as anti-inflammatory therapy for patients with mild, persistent asthma. The role that these drugs will play in clinical practice will become more apparent as additional experience is gained in their use. The results of clinical studies illustrate their potential: anti-LT agents reduce asthma symptoms, improve airway function, and decrease the need for concomitant beta 2-agonists and inhaled corticosteroids; the incidence of asthma exacerbations may also be reduced. Finally, because these agents are administered orally, they offer the potential for improved patient compliance relative to the more complicated forms of drug administration.

Zafirlukast improves asthma symptoms and quality of life in patients with moderate reversible airflow obstruction

BACKGROUND

Previous trials demonstrated the effectiveness of the leukotriene receptor antagonist zafirlukast in patients with mild-to-moderate asthma.

OBJECTIVES

We sought to assess the efficacy and safety of zafirlukast and its effect on patients' quality of life (QOL) during a 13-week, double-blind, placebo-controlled, multicenter trial in adults and adolescents with moderate reversible airflow obstruction.

METHODS

Patients (age range, 12 to 68 years) with total daytime asthma symptoms scores of 10 or greater over 7 consecutive days (maximum, 21/wk), FEV1 45% or greater but less than or equal to 80% of predicted value (>/=6 hours after beta2 -agonist), and reversible airway disease were randomized to 20 mg zafirlukast twice daily (nZ = 231) or placebo twice daily (nP = 223). Efficacy was assessed from changes in daytime and nocturnal symptoms, beta2 -agonist use, nasal congestion score, and pulmonary function. QOL was evaluated with a disease-specific Asthma Quality of Life Questionnaire. Safety was determined from adverse event information and clinical laboratory test results.

RESULTS

Zafirlukast was significantly (P <.001) more effective than placebo, with reductions from baseline in the daytime asthma symptoms score (-23%), nighttime awakenings with asthma (-19%), and beta2 -agonist use (-24%) and improvements from baseline in morning (+25 L/min) and evening (+18 L/min) peak expiratory flow rates. Compared with placebo, zafirlukast significantly (P </=.018) improved scores for QOL domains (activity limitations, symptoms, emotional function, and exposure to environmental stimuli) and overall QOL, with a significantly greater proportion of zafirlukast-treated patients demonstrating clinically meaningful improvements (>/=0.5-unit change from baseline; P </=.037). The safety profile of zafirlukast was clinically indistinguishable from that of placebo.

CONCLUSIONS

Zafirlukast is effective and well tolerated and improves QOL in the long-term treatment of patients with moderate reversible airflow obstruction.

Algorithm for the diagnosis and management of asthma: a practice parameter update: Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma and Immunology, the American College of Allergy, Asthma and Immunology, and the Joint Council of Allergy, Asthma and Immunology

This algorithm on the diagnosis and treatment of asthma is intended to complement and update the previously published Practice Parameters for the Diagnosis and Treatment of Asthma. Both documents were developed by the Joint Task Force on Practice Parameters, representing the AAAAI, ACAAI, and the JCAAI. The authors of this asthma algorithm have attempted to include all the elements essential for the diagnosis and care of patients with asthma. Every effort was made to keep the algorithm clear and concise, yet thorough and complete (Fig 1). Each component of the algorithm is elaborated further in a brief annotation. For further discussion, the reader is referred to the more extensive Practice Parameters for the Diagnosis and Treatment of Asthma.

Validation of the Doser, a new device for monitoring metered-dose inhaler use

BACKGROUND

Electronic monitoring of medication use has proved valuable in both clinical and research settings. The Doser, a new and inexpensive commercially available device for monitoring metered-dose inhaler (MDI) use, displays 3 measures of daily use of an attached MDI: (1) the daily total of actuations, (2) the number of doses remaining in the MDI, and (3) the number of actuations on each of the preceding 30 days for later recall.

OBJECTIVE

We sought to validate the accuracy of the Doser with several commonly prescribed MDIs.

METHODS

In the laboratory, clinic personnel actuated an MDI with an attached Doser several times in succession on 3 consecutive days and recorded each of the 3 measures of MDI use (study 1). In study 2 clinic personnel carried an MDI and attached Doser with them for 4 weeks, actuating the MDI according to a prescribed protocol each morning and evening and again recording each of the 3 measures of daily use. In addition, during 2 weeks of study 2, a thermistor-based Nebulizer Chronolog was attached to the MDI to electronically record the date and time of each actuation. In study 3 clinic patients had both a Doser and Nebulizer Chronolog attached to their routinely used inhalers for 2 weeks and a Doser alone during a separate 2-week period.

RESULTS

In study 1 agreement was 99% to 100% among the 3 Doser measures, and each measure agreed with actual use by self-report 97% of the time. In study 2 agreement among the 3 Doser measures of use ranged from 98% to 99%. Agreement between each of the 3 Doser measures and the Nebulizer Chronolog ranged from 90% to 93%. Agreement between each of the 3 Doser measures and actual use ranged from 96% to 97%, and the Nebulizer Chronolog agreed with actual use 93% of the time. In study 3 Doser and Nebulizer Chronolog agreement with patient self-report were 85% and 80%, respectively. Agreement between the Doser and Nebulizer Chronolog was 76%. Several failures of the thermistor-based Nebulizer Chronolog occurred, and occasional mechanical problems occurred with the Doser, primarily on particular types of MDI canisters.

CONCLUSION

The Doser provides an accurate measure of MDI use with most commonly prescribed medications and may be useful for monitoring MDI use by investigators, clinicians, and patients.

Oral glucocorticosteroid-sparing effect of budesonide administered by Turbuhaler: a double-blind, placebo-controlled study in adults with moderate-to-severe chronic asthma. Pulmicort Turbuhaler Study Group

OBJECTIVE

To determine the ability of budesonide via an inhaler (Pulmicort Turbuhaler; Astra Draco AB) to replace oral glucocorticosteroids (GCSs) in adult subjects with moderate-to-severe asthma.

DESIGN

Double-blind, randomized, and placebo-controlled study, with parallel groups.

SETTING

Multicenter study in outpatient setting.

PARTICIPANTS

Eighty men and 79 women, aged 20 to 69 years, with moderate-to-severe asthma and a mean FEV1 of 58.3% predicted normal. All subjects were receiving oral GCS treatment and 79% of subjects were also receiving inhaled beclomethasone dipropionate (BDP). The mean daily doses of prednisone at baseline, including converted dose of BDP, for the placebo, budesonide 400 microg, and budesonide 800 microg, respectively, were 19.7 mg, 19.5 mg, and 18.7 mg.

MEASUREMENTS AND INTERVENTIONS

After a 2-week baseline period, subjects entered a 20-week treatment period, during which the oral dose of prednisone was reduced by forced down-titration at 2-weekly intervals.

RESULTS

Subjects receiving 400 microg or 800 microg bid of budesonide achieved a significantly greater reduction (82.9% and 79.0% respectively) in oral GCS dose compared with placebo-treated subjects (27%; p<0.001). Two thirds of the subjects receiving budesonide were able to achieve sustained oral corticosteroid cessation, compared with 8% in the placebo group. Additionally, both doses of budesonide resulted in significant improvement in results of pulmonary function tests and asthma symptoms scores, and a significant decrease in the use of bronchodilator therapy. The mean plasma cortisol levels before and after adrenocorticotropic hormone stimulation increased most toward the normal range in the budesonide-treated groups compared with placebo-treated subjects.

CONCLUSION

Budesonide administered via Turbuhaler has a significant oral GCS-sparing capacity with maintained or improved asthma control in adult subjects with moderate-to-severe asthma.

Exercise-induced asthma

Exercise-induced asthma (EIA) is characterised by transient airway obstruction occurring after strenuous exertion. A fall of 10% or more in the FEV1 after exercise is diagnostic. Inhalation of large volumes of dry, cold air during exercise leads to loss of heat and water from the bronchial mucosa and airway cooling and drying. Proposed mechanisms for bronchoconstriction include: (i) mucosal drying and increased osmolarity stimulating mast cell degranulation; and (ii) rapid airway rewarming after exercise causing vascular congestion, increased permeability and oedema leading to obstruction. EIA symptoms start after exercise, peak 8 to 15 minutes after exercise and spontaneously resolve in about 60 minutes. A refractory period of up to 3 hours after recovery, during which repeat exercise causes less bronchospasm, has been observed. The amount of ventilation and the temperature of inspired air are important factors in determining the severity of EIA. Greater ventilation and cold, dry air increase the risk for EIA. Education regarding the nature and management of EIA is important not only for asthmatics but also for their families and coaches. With the proper precautions and workout techniques, there is no limit to what individuals with asthma can achieve in sports. Prevention is the main objective in managing EIA. Nonpharmacological measures include warming up before vigorous exertion, covering the mouth and nose in cold weather, exercising in warm, humidified environments if possible and warming down after exercise. Aerobic fitness and good control of baseline bronchial reactivity also help to diminish the effects of EIA. Inhaled beta-agonists are the medications of choice in EIA prophylaxis. Inhaled sodium cromoglycate (cromolyn sodium) or nedocromil may also be used. Agents that may be added if inhaled beta-agonists or sodium cromoglycate are not adequate include anticholinergic agents (such as ipratropium bromide), theophylline, calcium channel blockers, alpha-agonists, antihistamines and oral beta-agonists. Newer agents include antileukotriene agents, inhaled heparin and inhaled furosemide (frusemide).

Leukotriene activity modulation in asthma

Leukotrienes constitute a class of inflammatory mediators synthesised from arachidonic acid, a product of cell membrane metabolism. Synthesis occurs in the 5-lipoxygenase enzyme pathway, which produces several species of leukotrienes, each with characteristic biological activities. With regard to asthma, the leukotrienes are particularly important because of their ability to directly and potently mediate bronchoconstriction; in addition, they specifically stimulate the secretion of mucus into the airways and the extravasation of fluids and proteins into the airway tissues, both of which contribute to airway obstruction. A number of antileukotriene agents have been developed with the goal of modulating the inflammatory process in various disease states. These agents fall into 2 general classes: leukotriene receptor antagonists and leukotriene synthesis inhibitors. Results of antileukotriene agents in preclinical and clinical trials indicate that antileukotriene agents attenuate the response to challenges with inhaled leukotrienes, cold air, exercise, aspirin and allergen; in addition, they have shown efficacy in clinical asthma and have not been associated with serious adverse effects. Although results to date indicate that these medications are well tolerated and effective in the treatment of asthma, the recent approval by the FDA of 2 antileukotriene agents will give physicians further insight into how patients with asthma respond to them.

Antileukotriene agents

The antileukotriene agents, the first new class of asthma medications introduced in two decades, represent a promising new alternative in the continuing search for effective and safe therapy for chronic inflammation in asthma. The leukotrienes are inflammatory mediators whose effects on asthma include bronchoconstriction, increased vascular permeability, and increased mucus production. In chronic asthma, regular use of either leukotriene synthesis inhibitors or leukotriene receptor antagonists has improved pulmonary function and clinical symptoms significantly. Antileukotriene agents appear to be safe and well tolerated, although long-term studies will be needed to confirm this.

Salmeterol versus theophylline in the treatment of asthma

BACKGROUND

Although theophylline is recommended by current guidelines for the management of asthma in patients with persistent symptoms, theophylline has a narrow therapeutic index, requiring individual dose titration and regular monitoring of serum theophylline concentrations to avoid adverse effects.

OBJECTIVE

To compare the inhaled long-acting bronchodilator, salmeterol, with the oral bronchodilator, theophylline, in the maintenance treatment of asthma.

METHODS

In two multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel-group studies, patients received salmeterol aerosol 42 micrograms, extended-release theophylline capsules, or placebo twice daily for 12 weeks.

RESULTS

Of 638 adult and adolescent patients with moderate asthma who entered the prebaseline theophylline titration period, 154 were withdrawn prior to randomization (71 due to theophylline-related adverse effects); 484 patients comprised the intent-to-treat population. The mean serum theophylline concentration measured approximately seven hours postdose during the titration period in the theophylline group was 12.7 mg/L (70 mumol/L). The same dose during the treatment period resulted in a mean serum theophylline concentration between 7.6 to 7.9 mg/L (42-44 mumol/L) when measured approximately 12 hours postdose. Salmeterol was significantly more effective than theophylline or placebo in improving mean morning PEF over the entire 12 weeks (P < or = .02). Mean predose FEV1 improved significantly with salmeterol compared with placebo (P < .001); there was no difference between theophylline and placebo. Salmeterol was also significantly more effective than theophylline or placebo (P < .02) in improving asthma symptoms, reducing nighttime awakenings, and reducing the daily use of albuterol. After 12 weeks of treatment, patients in the salmeterol group expressed significantly greater overall satisfaction with their asthma medication than did patients who received theophylline (P < .01). Patients in the theophylline group experienced more gastrointestinal adverse events than did patients in the salmeterol group (P < .05).

CONCLUSION

Salmeterol, 42 mg twice daily, was better tolerated and significantly more effective than extended-release theophylline twice daily in the maintenance treatment of asthma.

Treatment of the unusually difficult asthmatic patient

Various practice parameters have emphasized a step-wise approach to the treatment of asthma utilizing high doses of inhaled corticosteroids, i.e., 2000 ug per day for the most difficult-to-manage asthmatic patient, along with maximum bronchodilator therapy. The use of such vigorous therapy presupposes that various triggers that perpetuate asthma have been considered and hopefully eliminated or diminished, such as occupational incitants, gastroesophageal reflux, and concomitant medication such as beta blockers and perhaps difficult-to-recognize allergen stimulation. As new therapies emerge, their role in the treatment of a severe subgroup of the population remains uncategorized and will only be clarified with personal experience and appropriate double-blind studies. For example, there are data to support the concept that salmeterol plus moderate dose aerosol corticosteroids is superior to high dose corticosteroid aerosols. Theoretically, the use of anti-leukotrienes for a patient with aspirin idiosyncrasy may be superior to other combinations as would be conjectured from aspirin challenge data. Lidocaine has recently been employed in severe asthmatics, and preliminary data suggest benefit. The purpose of this review is to summarize some of our knowledge regarding medications that are either steroid-sparing or that might be useful in a subgroup of asthmatic patients with severe asthma.

Overview of comorbid associations of allergic rhinitis

Allergic rhinitis affects approximately 20% of the U.S. population. An association between allergic rhinitis and conditions including asthma, sinusitis, otitis media, nasal polyposis, respiratory infections, and even orthodontic malocclusions has been observed. Clinical research has identified shared pathogenic mechanisms, epidemiologic correlations, and findings from allergy testing to indicate that these conditions represent long-term physical consequences in allergic individuals. The positive response of patients afflicted with these conditions to antiallergic treatment further enhances the association between allergic rhinitis and other airway diseases. The use of nasal corticosteroids in patients with rhinitis and asthma reduces not only rhinitis symptoms but also asthma symptoms and airway reactivity to methacholine challenge. Similarly, antihistamines, with or without decongestants, result in improvement of objective measurements of pulmonary function. In the treatment of acute sinusitis, the combination of an intranasal corticosteroid and an antibiotic provides greater benefit than an antibiotic alone. Treatment strategies for allergic rhinitis should be directed at controlling the symptoms of allergic rhinitis and reducing the development of physical complications in susceptible persons. Three techniques for the treatment of allergic rhinitis are used, including avoidance of offending allergens, selection of appropriate pharmaceuticals, and allergy immunotherapy. Appropriate treatment may spare some patients of related airway diseases and may also reduce the overall cost of care. The broadened scope of allergic rhinitis and increased prevalence of IgE-mediated diseases have heightened awareness regarding the profound consequences of allergic rhinitis and the importance of effective treatment.

Alternative treatments in the patient with intractable asthma

Various medications have been suggested as alternative therapy for oral corticosteroids in the treatment of asthma, due to the known adverse effects of oral corticosteroids. Examples of such medications include methotrexate, gold, cyclosporin A, hydroxychloroquine, and dapsone, all of which have a significant side-effect profile. Intravenous gammaglobulin therapy used as an immuno-modulator has little if any side-effects, but it is very costly. The antileukotrienes represent a safe class of medications that may be of particular benefit to certain subgroups of asthmatic patients. Antileukotrienes have become commercially available in other countries.

Management of asthma with zafirlukast. Clinical experience and tolerability profile

This article reviews the literature on the use of zafirlukast in the treatment of asthma, with particular focus on its ability to attenuate the asthma-causing effects of leukotrienes. Leukotrienes produced by the 5-lipoxygenase enzyme pathway have various biological activities. These include the specific inflammatory effects associated with asthma, such as increased vascular permeability, enhanced mucus production and decreased mucociliary transport. Leukotriene receptors in the airways also mediate a potent bronchoconstriction and this is particularly important in asthma. Zafirlukast was developed with the goal of attenuating the inflammatory effects of leukotrienes in asthma. Zafirlukast attenuates the responses to inhaled leukotrienes and allergen challenges, and produces beneficial effects in cold air- and exercise-induced asthma. Zafirlukast has been compared with placebo and sodium cromoglycate in clinical trials involving asthma patients. Zafirlukast brings about a significant bronchodilation within 1 hour of administration that is additive to the effects of beta 2 agonists. These studies showed that zafirlukast improves pulmonary function and reduces the symptoms of asthma. Zafirlukast is well tolerated with an incidence of adverse events similar to that seen with the use of placebo. As an oral twice-daily formulation, zafirlukast may improve patient adherence to therapy. As an anti-inflammatory agent, zafirlukast may in the future find a role in the treatment of a variety of diverse inflammatory conditions.

Leukotriene inhibitors and antagonists in asthma

OBJECTIVE

This article reviews the literature on the effects of leukotrienes in asthma. In particular, the ability of recently developed receptor antagonists and synthesis inhibitors to attenuate the asthma-causing effects of leukotrienes is examined.

DESIGN

Published literature on the role of leukotrienes in asthma was reviewed. Reports of research on agents that inhibit the synthesis of leukotrienes or block leukotriene receptors were also studied.

RESULTS

Leukotrienes are endogenous molecules formed by the breakdown of a membrane constituent, arachidonic acid, via the 5-lipoxygenase enzyme pathway. This pathway ultimately produces several species of leukotrienes with various biologic activities, including generalized inflammatory effects associated with asthma: increased vascular permeability, enhanced mucous production, and decreased mucociliary transport. Particularly important in asthma, leukotriene receptors on the airways mediate a potent bronchoconstriction. Two general types of drugs have been developed with the goal of attenuating the leukotrienes' effects in inflammation and asthma: the leukotriene receptor blockers and the leukotriene synthesis inhibitors (eg, 5-lipoxygenase inhibitors).

CONCLUSIONS

The antileukotriene drugs attenuated the responses to inhaled leukotrienes and allergen challenges. These agents produced beneficial effects in cold-, exercise-, and aspirin-induced asthma, as well as clinical asthma. Many of these medications appear to be effective in the treatment of asthma; however, further clinical research is needed to determine which patients would benefit most from their use.

Implications of practice parameters (guidelines)

Practice parameters (guidelines) have been developed for many years. The first such parameter, developed by a Joint Task Force of the American Academy of Allergy and Immunology, and the American College of Allergy and Immunology, was on the diagnosis and treatment of patients with asthma. It was sent in notebook form to members of the Academy and College in 1993. An updated version will be published as a supplement to the Journal of Allergy and Clinical Immunology sometime in 1995. Although the overriding consideration in the development of these parameters is to improve the level of care for patients, and by doing so to decrease asthma morbidity and mortality, recent guidelines have also emphasized cost factors, especially those that are now being developed by managed care organizations. Practice parameters can also reduce malpractice liability, and studies have even shown a reduction in hospital admissions by instituting relatively simple measures of patient behavior. There is no doubt that practice parameters will become an important part of our everyday life.

Comparison of the bronchodilatory effects of cetirizine, albuterol, and both together versus placebo in patients with mild-to-moderate asthma

BACKGROUND

Many potential users of the H1 antihistamine cetirizine are asthmatic and may be using inhaled albuterol. This study was conducted to assess the possible bronchodilatory effect of cetirizine in patients with mild-to-moderate asthma and to determine whether cetirizine interacts with albuterol.

METHODS

In a randomized, double-blind, placebo-controlled, crossover study, the effects on pulmonary function of 5, 10, and 20 mg oral doses of cetirizine with and without inhaled albuterol (180 micrograms) were determined in 12 patients at 11 time points over 8 hours. The primary measure of efficacy was forced expiratory volume in 1 second (FEV1).

RESULTS

Cetirizine with or without albuterol significantly increased FEV1, peak expiratory flow rate, and forced expiratory flow rate between 25% and 75% of vital capacity relative to baseline and placebo but did not have a significant effect on forced vital capacity. The effect of 20 mg of cetirizine on FEV1 was generally greater than that of 10 or 5 mg, but the difference was statistically significant only at the 30-minute time point (p < 0.05). All three cetirizine doses produced significantly greater increases than placebo in FEV1 and forced expiratory flow rate between 25% and 75% of vital capacity for 8 hours and in peak expiratory flow rate for 7 hours (p < 0.02). Albuterol alone had a significant effect on the four pulmonary function variables from 1 to 5 hours after baseline (p < 0.05), which is consistent with albuterol's recommended dosing frequency of every 4 to 6 hours. Albuterol alone increased FEV1 significantly more than 5 mg of cetirizine alone but not 10 mg or 20 mg of cetirizine alone at 60, 90, and 120 minutes after baseline, but all three doses of cetirizine increased FEV1 significantly more than albuterol 7 and 8 hours after baseline (p < 0.05), indicating that the bronchodilatory action of cetirizine lasts longer than that of albuterol. Cetirizine neither potentiated nor inhibited the bronchodilatory action of albuterol, but the two drugs appeared to have an additive bronchodilatory effect. None of the cetirizine treatments caused a worsening of pulmonary function, and all were well tolerated.

CONCLUSIONS

Cetirizine has a significant bronchodilatory effect in patients with mild-to-moderate asthma and can be used to treat concomitant conditions (e.g., allergic rhinitis) without concern that it will interfere with the bronchodilatory effect of albuterol or cause worsening of asthma by itself.

A comparison of imaging techniques in patients with chronic sinusitis (X-ray, MRI, A-mode ultrasound)

Thirty-five patients age 9 to 67 were evaluated for chronic sinusitis by history, physical and laboratory examination, and imaging techniques (X-ray, magnetic resonance imaging (MRI) and flexible rhinoscopy). MRI was the most predictive. To establish the diagnosis of sinusitis, it was more sensitive than plain X-ray for intrasinus disease. Findings of edema, erythema, and drainage on flexible rhinoscopy were consistent with chronic sinusitis and were confirmed by MRI and sinus X-rays in 41% of the cases. Nasal smears for polymorphonuclear cells and eosinophils were suggestive of a diagnosis of chronic sinusitis, but other laboratory tests (CBC, sedimentation rate, quantitative immunoglobulins, total IgEs) were of very limited value in the diagnosis of chronic sinusitis.

The common cold: current therapy and natural history

Despite its prevalence, the common cold is complicated and can be difficult to treat, even symptomatically. There is still no cure for the myriad of viruses that cause the common cold. Many of the most popular remedies are either ineffective or counterproductive. This paper reviews the causes and course of upper respiratory infections, and discusses treatment options, including a new anticholinergic aqueous formulation for controlling rhinorrhea.

Albuterol aerosol versus albuterol Rotacaps in exercise-induced bronchospasm in children

The purpose of this study was to determine the safety and effectiveness of albuterol aerosol 180 micrograms and albuterol powder 200 micrograms in the prevention of exercise-induced bronchospasm in children. Forty-six patients aged 4-11 years with asthma and exercise-induced bronchospasm were enrolled in this randomized, double-blind, single-dose, three-way crossover study comparing albuterol aerosol, albuterol powder, and placebo. Exercise challenge was performed at the screening visit for qualifying and baseline determinations of pulmonary function and then 15 min after drug administration at each of three visits. Prevention of exercise-induced bronchospasm was assessed by comparing across all treatment groups the percentage change in FEV1 from pre- to postexercise, the percentage of patients protected by treatment, postexercise minimum FEV1, and postexercise change in FEV1. Safety was assessed by observation of clinical adverse events, laboratory tests, physical examination, electrocardiogram and rhythm strips, vital signs, and pulmonary auscultation. Forty-four patients completed the study. Mean postexercise FEV1 decreased 6% from preexercise values when patients were treated with either albuterol formulation; FEV1 decreased 23% when patients were treated with placebo. Exercise-induced bronchospasm was prevented in 95% of patients when treated with albuterol powder, in 91% treated with albuterol aerosol, and in 57% treated with placebo. Patients maintained significantly higher mean minimum FEV1 values after treatment with albuterol powder and albuterol aerosol than when treated with placebo. Treatment with either albuterol formulation produced a significantly smaller decrease in mean FEV1 from pre- to postexercise than treatment with placebo. No drug-related adverse events were reported, and safety assessments were within normal limits.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of 6 weeks of therapy with oral doses of ICI 204,219, a leukotriene D4 receptor antagonist, in subjects with bronchial asthma. ACCOLATE Asthma Trialists Group

The efficacy of 6 wk of therapy with oral ICI 204,219, a selective leukotriene D4 (LTD4) receptor antagonist, was evaluated in subjects with moderate asthma during a multicenter, double-blind, randomized, placebo-controlled, dose-ranging study. Subjects who entered the trial had been chronically treated for asthma with beta agonist alone or in combination with theophylline. Subjects were randomized to treatment with twice daily doses of ICI 204,219 (5, 10, or 20 mg) or placebo if they had an FEV1 between 40 and 75% of predicted values without bronchodilator therapy and a daytime asthma score > 10 (range 0 to 21 per wk) for 7 consecutive d. Efficacy was evaluated from the results of symptom assessments, pulmonary function tests, and rescue medication use. Of 276 subjects randomized to treatment, 266 (10 mg, n = 66; 20 mg, n = 67; 40 mg, n = 67; placebo, n = 66) were analyzed for efficacy. Diary card assessments showed that treatment with increasing doses of ICI 204,219 linearly improved five efficacy criteria without increasing the number or severity of adverse events. The 40 mg dose was more effective than placebo (p < 0.05) in reducing nighttime awakenings, first morning asthma symptoms, the daytime asthma score, and albuterol use and in increasing evening peak expiratory flow (PEF) rates as well as FEV1. Compared with baseline measurements, the 40 mg dose decreased awakenings by 46%, albuterol use by 30%, and daytime symptoms by 26% and increased FEV1 by 11%. ICI 204,219 improves objective and subjective measures of asthma severity in moderately ill asthmatic subjects and may provide a new treatment option for the disease.

Update on exercise-induced asthma

Exercise-induced asthma (EIA) is a temporary increase in airway resistance that occurs after several minutes of strenuous exercise, generally eight to 15 minutes after the patient has stopped exercising. Some individuals experience a secondary reduction in pulmonary function several hours later, the so-called late-phase response. Many physicians believe that EIA is caused by respiratory water loss or airway cooling. Others incriminate tissue mast cells of the lung. The role of histamine is uncertain because it is detected inconsistently in the serum after an attack. Recent studies suggest that the release of sulfidopeptide leukotrienes may play a major role in EIA. Although the exact pathophysiology has yet to be determined, several highly successful treatment regimens have been developed. Preventive pharmacologic treatment with aerosolized beta-agonists is more successful than treatment with cromolyn sodium; however, coadministration of these agents produces significant symptomatic improvement in more than 90% of patients. Other useful medications include antihistamines, anticholinergic agents, theophylline, oral beta-agonists, calcium channel blockers, alpha-adrenergic antagonists, nedocromil, and leukotriene antagonists. Exercise-induced asthma may be suppressed with warm humidified air. This environment can be simulated by swimming in a heated pool or wearing a scarf over the nose and mouth in cold weather.

As-needed medication use in asthma usage patterns and patient characteristics

Daily inhaled bronchodilator medication usage was recorded using an electronic device and airway obstruction by daily peak flow measurement. The demographic, clinical, and psychological characteristics of the subjects were noted. Subjects were allocated to as-needed (prn) medication usage groups according to the mean number of inhaler activations on days with zero, moderate, and severe airway obstruction. Segregation into arbitrary and nonarbitrary use, and into overuse, appropriate use, and underuse resulted in six usage groups. Appropriate use was observed in only 10 of 39 subjects. The major psychological variable to differ among groups was the MMPI variable Pt, representing general anxiety. Arbitrary users had a significantly higher mean score than nonarbitrary users. The variable Specific Internal Awareness, representing a perceived difficulty in recognizing the premonitory symptoms of an asthma attack, also differed among the usage groups, with arbitrary users having the lowest scores. These findings raise the possibility that reliance on an objective measurement of airway obstruction rather than on subjective symptomatology might enhance compliance with prn medication in some patients.

Clinical comparison of cefuroxime axetil and amoxicillin/clavulanate in the treatment of patients with acute bacterial maxillary sinusitis

PURPOSE

This multicenter study compared the clinical and bacteriologic efficacy of two oral antibiotics, cefuroxime axetil and amoxicillin/clavulanate, in the treatment of acute bacterial maxillary sinusitis.

PATIENTS AND METHODS

Three hundred seventeen patients with clinical and radiographic evidence of acute maxillary sinusitis were enrolled at nine centers and were randomly assigned to receive 10 days of treatment with cefuroxime axetil 250 mg twice daily (n = 157) or amoxicillin/clavulanate 500 mg three times daily (n = 160). Patients were assessed for both clinical and bacteriologic responses once during treatment (5 to 7 days) and twice after treatment (1 to 3 days and 4 weeks). Bacteriologic assessments were based on needle aspirates of the maxillary sinus obtained pretreatment and, when possible, at the first posttreatment visit.

RESULTS

Organisms were isolated from the pretreatment sinus aspirates of 198 of 317 (62%) patients, with the primary isolates being Streptococcus pneumoniae (22%), Haemophilus spp. (17%), Staphylococcus aureus (13%), and Haemophilus influenzae (10%). A satisfactory clinical outcome (cure or improvement) was achieved in 85% (98 of 115) and 82% (102 of 124) of the clinically evaluable patients treated with cefuroxime axetil or amoxicillin/clavulanate, respectively (P = 0.446). With respect to the eradication of the bacterial pathogens, a satisfactory outcome (cure or presumed cure) was obtained in 84% (31 of 37) and 87% (34 of 39) of bacteriologically evaluable patients treated with cefuroxime axetil or amoxicillin/clavulanate, respectively (p = 0.567). Treatment with amoxicillin/clavulanate was associated with a significantly higher incidence of drug-related adverse events (13% versus 3%, p = 0.001), particularly diarrhea (8% versus 1%, p = 0.001). Two patients in the cefuroxime axetil group and three patients in the amoxicillin/clavulanate group withdrew from the study due to adverse events.

CONCLUSIONS

Our results indicate that cefuroxime axetil twice a day is as effective as amoxicillin/clavulanate three times a day in the treatment of acute bacterial maxillary sinusitis but produces fewer adverse effects.

The role of allergy in sinusitis in adults

Allergic sinus disease in adults has not been definitively established. On the other hand, sinusitis is more common in allergic individuals than control subjects. Nasal provocation studies with allergens produce clinical findings and radiographic evidence suggestive of allergic sinusitis. Studies that use single-photon emission computerized tomography do not confirm direct entry of pollens into the sinuses. Fungal sinusitis typically occurs in patients with allergic rhinitis and nasal obstruction for many years. Patients often have an elevated specific IgE and total IgE with positive skin tests to the fungus involved. The diagnosis is confirmed by computed tomographic scan or magnetic resonance imaging of the sinuses. There is no direct fungal invasion. Many patients who have chronic severe sinusitis, asthma, and frequently aspirin idiosyncrasy appear to have immunologic reactions in the sinuses (and bronchial tissue). Histologic findings of the sinus mucosa show infiltration with plasma cells and eosinophils. Immunofluorescent stains show IgE dispersed throughout the tissue possibly in plasma cells. An intense linear stain for IgD is found along the epithelial side of the basement membrane.

Common triggers of asthma

Control of asthma is enhanced when careful consideration is given to underlying mechanisms. Patients can be advised of ways to avoid or minimize contact with offending allergens, and, in some cases, pharmacologic management may not be necessary. Care must be taken when treating patients with concomitant disorders, such as hyperthyroidism. Also, psychological factors may have a role in exacerbating symptoms in suggestible patients. Noncompliance, in some cases due to inability to pay for medication, may be an unrecognized cause of treatment failure.

Compliance in clinical trials of two nonbronchodilator, antiasthma medications

An electronic monitoring device was used to assess patient compliance during clinical trials of two new aerosolized nonbronchodilator, antiasthma drugs. Compliance was poor, but similar, in both trials. Patients took the study drug as instructed on a mean of 37.3% days (range 10% to 77%) in one trial and 37.4% days (range 0% to 63%) in the other. Both underuse and overuse were observed. Underuse was seen on a mean of 38.9% days (range 9% to 81%) and 46.0% (range 15% to 80%) respectively; overuse on a mean of 23.5% days (range 6% to 54%) and 16.6% days (range 0% to 41%). In some patients ten or more activations of the device were recorded at the same time. In six patients such multiple simultaneous activations were recorded on two or more separate days. These patients were among the most noncompliant in the study. Multiple simultaneous activations frequently followed underuse days or preceded followup visits, suggesting the possibility of duplicity. Overall compliance was such that valid conclusions about efficacy of the drugs could only have been drawn in six of 34 patients.

Asthma and chronic obstructive lung disease: a pharmacologic approach

Changing concepts are emerging that should improve our ability to adequately treat asthma. This volume of Disease-a-Month reviews the triggers and the role of inflammation in asthma, and outlines the treatment of acute asthma as well as the chronic management of reversible obstructive airways disease. There is general agreement that sympathomimetics are the treatment of choice for acute severe asthma. The role of theophylline for acute symptoms has been downplayed, and the role of corticosteroids continues to be debated. However, most authorities agree that patients with severe asthma will benefit from the addition of corticosteroids to the program. For the chronic management of asthma, appreciation that inflammation is a perpetuating feature suggests that treatment should generally be directed toward the inflammation. Corticosteroid aerosols have taken on greater prominence and have been advocated as the first line of approach. New concepts regarding the role of allergy in the perpetuation of asthma and the role of immunotherapy in its amelioration also have emerged. Medications not previously thought to be beneficial are being actively investigated. They include gold, methotrexate, and even intravenous gamma globulin.