Comparison of aerosolized glycopyrrolate and metaproterenol in acute asthma

G Protein-Coupled Receptors in Asthma Therapy: Pharmacology and Drug Action

Asthma is a heterogeneous inflammatory disease of the airways that is associated with airway hyperresponsiveness and airflow limitation. Although asthma was once simply categorized as atopic or nonatopic, emerging analyses over the last few decades have revealed a variety of asthma endotypes that are attributed to numerous pathophysiological mechanisms. The classification of asthma by endotype is primarily routed in different profiles of airway inflammation that contribute to bronchoconstriction. Many asthma therapeutics target G protein-coupled receptors (GPCRs), which either enhance bronchodilation or prevent bronchoconstriction. Short-acting and long-acting β 2-agonists are widely used bronchodilators that signal through the activation of the β 2-adrenergic receptor. Short-acting and long-acting antagonists of muscarinic acetylcholine receptors are used to reduce bronchoconstriction by blocking the action of acetylcholine. Leukotriene antagonists that block the signaling of cysteinyl leukotriene receptor 1 are used as an add-on therapy to reduce bronchoconstriction and inflammation induced by cysteinyl leukotrienes. A number of GPCR-targeting asthma drug candidates are also in different stages of development. Among them, antagonists of prostaglandin D2 receptor 2 have advanced into phase III clinical trials. Others, including antagonists of the adenosine A2B receptor and the histamine H4 receptor, are in early stages of clinical investigation. In the past decade, significant research advancements in pharmacology, cell biology, structural biology, and molecular physiology have greatly deepened our understanding of the therapeutic roles of GPCRs in asthma and drug action on these GPCRs. This review summarizes our current understanding of GPCR signaling and pharmacology in the context of asthma treatment. SIGNIFICANCE STATEMENT: Although current treatment methods for asthma are effective for a majority of asthma patients, there are still a large number of patients with poorly controlled asthma who may experience asthma exacerbations. This review summarizes current asthma treatment methods and our understanding of signaling and pharmacology of G protein-coupled receptors (GPCRs) in asthma therapy, and discusses controversies regarding the use of GPCR drugs and new opportunities in developing GPCR-targeting therapeutics for the treatment of asthma.

Long-Acting Muscarinic Antagonists for Difficult-to-Treat Asthma: Emerging Evidence and Future Directions

Asthma is a complex disease where many patients remain symptomatic despite guideline-directed therapy. This suggests an unmet need for alternative treatment approaches. Understanding the physiological role of muscarinic receptors and the parasympathetic nervous system in the respiratory tract will provide a foundation of alternative therapeutics in asthma. Currently, several long-acting muscarinic antagonists (LAMAs) are on the market for the treatment of respiratory diseases. Many studies have shown the effectiveness of tiotropium, a LAMA, as add-on therapy in uncontrolled asthma. These studies led to FDA approval for tiotropium use in asthma. In this review, we discuss how the neurotransmitter acetylcholine itself contributes to inflammation, bronchoconstriction, and remodeling in asthma. We further describe the current clinical studies evaluating LAMAs in adult and adolescent patients with asthma, providing a comprehensive review of the current known physiological benefits of LAMAs in respiratory disease.

Role of muscarinic antagonists in asthma therapy

INTRODUCTION

Higher parasympathetic tone has been reported in asthmatics. In general, cholinergic contractile tone is increased by airway inflammation associated with asthma. Nevertheless, the role of muscarinic antagonists for the treatment of asthma has not yet been clearly defined. Areas covered: The use of SAMAs and LAMAs in asthma has been examined and discussed according with the published evidence. Particular attention has been given to the large Phase III clinical trial program designed to evaluate the efficacy and safety of tiotropium respimat added to standard treatment in adults, adolescents and children with persistent asthma across the spectrum of asthma severity. Expert commentary: The current evidence is that in patients with poorly controlled severe asthma despite the use of ICS and LABA, the addition of tiotropium significantly increases the time to the first severe exacerbation and provides a modest but sustained bronchodilation. Identical results should be produced using other LAMAs. In any case, the documentation that, at least in animal or in vitro models, LAMAs show significant anti-inflammatory and anti-proliferative capacities and are able to inhibit airway remodeling induced by allergens makes a strong presumption that the use of LAMAs in asthma may go beyond the simple bronchodilator effect.

Combined inhaled beta-agonist and anticholinergic agents for emergency management in adults with asthma

BACKGROUND

Inhaled short-acting anticholinergics (SAAC) and short-acting beta₂-agonists (SABA) are effective therapies for adult patients with acute asthma who present to the emergency department (ED). It is unclear, however, whether the combination of SAAC and SABA treatment is more effective in reducing hospitalisations compared to treatment with SABA alone.

OBJECTIVES

To conduct an up-to-date systematic search and meta-analysis on the effectiveness of combined inhaled therapy (SAAC + SABA agents) vs. SABA alone to reduce hospitalisations in adult patients presenting to the ED with an exacerbation of asthma.

SEARCH METHODS

We searched MEDLINE, Embase, CINAHL, SCOPUS, LILACS, ProQuest Dissertations & Theses Global and evidence-based medicine (EBM) databases using controlled vocabulary, natural language terms, and a variety of specific and general terms for inhaled SAAC and SABA drugs. The search spanned from 1946 to July 2015. The Cochrane Airways Group provided search results from the Cochrane Airways Group Register of Trials which was most recently conducted in July 2016. An extensive search of the grey literature was completed to identify any other potentially relevant studies.

SELECTION CRITERIA

Included studies were randomised or controlled clinical trials comparing the effectiveness of combined inhaled therapy (SAAC and SABA) to SABA treatment alone to prevent hospitalisations in adults with acute asthma in the emergency department. Two independent review authors assessed studies for inclusion using pre-determined criteria.

DATA COLLECTION AND ANALYSIS

For dichotomous outcomes, we calculated individual and pooled statistics as risk ratios (RR) or odds ratios (OR) with 95% confidence intervals (CI) using a random-effects model and reporting heterogeneity (I²). For continuous outcomes, we reported individual trial results using mean differences (MD) and pooled results as weighted mean differences (WMD) or standardised mean differences (SMD) with 95% CIs using a random-effects model.

MAIN RESULTS

We included 23 studies that involved a total of 2724 enrolled participants. Most studies were rated at unclear or high risk of bias.Overall, participants receiving combination inhaled therapy were less likely to be hospitalised (RR 0.72, 95% CI 0.59 to 0.87; participants = 2120; studies = 16; I² = 12%; moderate quality of evidence). An estimated 65 fewer patients per 1000 would require hospitalisation after receiving combination therapy (95% 30 to 95), compared to 231 per 1000 patients receiving SABA alone. Although combination inhaled therapy was more effective than SABA treatment alone in reducing hospitalisation in participants with severe asthma exacerbations, this was not found for participants with mild or moderate exacerbations (test for difference between subgroups P = 0.02).Participants receiving combination therapy were more likely to experience improved forced expiratory volume in one second (FEV₁) (MD 0.25 L, 95% CI 0.02 to 0.48; participants = 687; studies = 6; I² = 70%; low quality of evidence), peak expiratory flow (PEF) (MD 36.58 L/min, 95% CI 23.07 to 50.09; participants = 1056; studies = 12; I² = 25%; very low quality of evidence), increased percent change in PEF from baseline (MD 24.88, 95% CI 14.83 to 34.93; participants = 551; studies = 7; I² = 23%; moderate quality of evidence), and were less likely to return to the ED for additional care (RR 0.80, 95% CI 0.66 to 0.98; participants = 1180; studies = 5; I² = 0%; moderate quality of evidence) than participants receiving SABA alone.Participants receiving combination inhaled therapy were more likely to experience adverse events than those treated with SABA agents alone (OR 2.03, 95% CI 1.28 to 3.20; participants = 1392; studies = 11; I² = 14%; moderate quality of evidence). Among patients receiving combination therapy, 103 per 1000 were likely to report adverse events (95% 31 to 195 more) compared to 131 per 1000 patients receiving SABA alone.

AUTHORS' CONCLUSIONS

Overall, combination inhaled therapy with SAAC and SABA reduced hospitalisation and improved pulmonary function in adults presenting to the ED with acute asthma. In particular, combination inhaled therapy was more effective in preventing hospitalisation in adults with severe asthma exacerbations who are at increased risk of hospitalisation, compared to those with mild-moderate exacerbations, who were at a lower risk to be hospitalised. A single dose of combination therapy and multiple doses both showed reductions in the risk of hospitalisation among adults with acute asthma. However, adults receiving combination therapy were more likely to experience adverse events, such as tremor, agitation, and palpitations, compared to patients receiving SABA alone.

Muscarinic antagonists in early stage clinical development for the treatment of asthma

INTRODUCTION

Parasympathetic neurons utilize the neurotransmitter acetylcholine to modulate and constrict airway smooth muscles at the muscarinic acetylcholine receptor. Inhaled agents that antagonize the muscarinic (M) acetylcholine receptor, particularly airway M3 receptors, have increasing data supporting use in persistent asthma. Areas covered: Use of inhaled long-acting muscarinic antagonists (LAMA) in asthma is explored. The LAMA tiotropium is approved for maintenance in symptomatic asthma patients despite the use of inhaled corticosteroids (ICS), leukotriene receptor antagonists (LTRA) and/or long-acting beta₂ agonists (LABA). LAMA agents currently approved for chronic obstructive pulmonary disease (COPD) include tiotropium, glycopyrrolate/glycopyrronium, umeclidinium and aclidinium. These agents are reviewed for their pharmacological differences and clinical trials in asthma. Expert opinion: Current guidelines place inhaled LAMAs as adjunctive maintenance therapy in symptomatic asthma not controlled by an ICS and/or a LTRA. LAMA agents will play an increasing role in moderate to severe symptomatic asthma patients. Additional LAMA agents are likely to seek a maintenance indication perhaps as a combined inhaler with an ICS or with an ICS and a LABA. These fixed-dose combination inhalers are being tested in COPD and asthma patients. Once-a-day dosing of inhaled LAMA agents in severe asthma patients will likely become the future standard.

Glycopyrrolate does not reduce the incidence of perioperative adverse events in children with upper respiratory tract infections

Two recent studies have identified copious secretions as an independent risk factor for perioperative adverse events in children who present for elective surgery in the presence of an upper respiratory tract infection (URI). We designed this study, therefore, to determine whether the administration of the anticholinergic drug, glycopyrrolate, to children with URIs would reduce the incidence of adverse perioperative respiratory events. One hundred thirty children (1 mo to 18 yr of age) who presented for elective surgery with a URI were randomized to receive either 0.01 mg/kg glycopyrrolate or placebo and were followed for the appearance and severity of any perioperative respiratory adverse events. The two groups were similar with respect to demographics, presenting URI symptoms, anesthetic management, and surgical procedure. In the intention-to-treat analysis, there were no statistical differences in the incidence or severity of perioperative respiratory adverse events between the glycopyrrolate and placebo groups (45.2% vs 37.5% respectively, P = NS). Furthermore, there were no differences in outcome between the two groups when children with congestion and secretions were analyzed separately (45.0% vs 37.0%, respectively). However, compared with the placebo group, children in the glycopyrrolate group had significantly shorter discharge times (83.9 min vs 111.4 min, P = 0.024), and significantly less postoperative nausea and vomiting (10.7% vs 33.3%, P = 0.005). These results suggest that glycopyrrolate, administered after induction of anesthesia to children with URIs, does not reduce the incidence of perioperative respiratory adverse events, and thus may not be clinically indicated for routine use in this population.

Glycopyrrolate causes prolonged bronchoprotection and bronchodilatation in patients with asthma

INTRODUCTION

Inhaled anticholinergic drugs are effective bronchodilators in the treatment of COPD, and tiotropium bromide has recently been introduced as a once-daily bronchodilator for use as a maintenance treatment. Racemic glycopyrrolate is an anticholinergic drug that has been used orally to control gastric acidity, parenterally as an antisialogogue and to reverse neuromuscular blockade, and has been studied by inhalation for asthma and COPD.

DESIGN AND OBJECTIVE

We investigated the duration of protection against the constrictor effects of inhaled methacholine of a single dose of inhaled nebulized racemic glycopyrrolate (0.5, 1.0, and 2.0 mg) compared with ipratropium bromide (0.5 mg) and placebo in 10 atopic asthmatic volunteers in a double-blind, five-way, crossover study.

RESULTS

Protection against methacholine-induced bronchospasm after administering glycopyrrolate was maintained to 30 h, the last time point measured. Both bronchodilatation and bronchoprotection were significantly longer with glycopyrrolate than after ipratropium bromide, and bronchoprotection was significant at all time points from 2 to 30 h compared to placebo. Dryness of the mouth and nose was described in 18% of patients after the highest dose of glycopyrrolate.

CONCLUSIONS

The prolonged bronchodilator response and the protection against methacholine-induced bronchospasm demonstrated in asthma suggests that inhaled racemic glycopyrrolate would be superior to ipratropium bromide for treatment of stable COPD.

Inhalation of calcium channel blocking agents protects against methacholine-induced bronchoconstriction

The calcium channel blockers, diltiazem and verapamil, and the beta agonist orciprenaline sulfate all demonstrated significant protection against methacholine-induced bronchoconstriction in 11 stable asthmatics (5 males and 6 females). Ten and 20 mg of inhaled diltiazem, 5 mg of verapamil or 30 mg of orciprenaline administered 15 min before stepwise increasing doses of methacholine hydrochloride produced significant reduction in respiratory resistance (Rrs), minimum dose of methacholine hydrochloride required for Rrs increase (Dmin) and bronchial reactivity measured with an Astograph. The mechanism of action of the calcium channel blockers is presumably at the level of the smooth muscle cells themselves. The combination of positive influence and lack of any adverse effect on blood pressure or heart rate with any of the agents tested indicates that their clinical application for alleviation of acute asthma can be recommended.

New medications for asthma

The therapy for chronic stable asthma and acute asthma exacerbations continues to evolve as the pathogenesis of asthma becomes better understood. Although the role of many standard therapies for asthma is well established, some carry significant side effects. The newer anti-inflammatory medications have demonstrated both therapeutic benefit as well as reassuring safety profiles. The challenge of the future is to incorporate the newer medications described, as well as those still being examined, into a treatment regimen that can deliver maximal therapeutic benefit with the lowest possible incidence of side effects.

Pharmacological characterization of the muscarinic receptor antagonist, glycopyrrolate, in human and guinea-pig airways

1. In this study we have evaluated the pharmacological profile of the muscarinic antagonist glycopyrrolate in guinea-pig and human airways in comparison with the commonly used antagonist ipratropium bromide. 2. Glycopyrrolate and ipratropium bromide inhibited EFS-induced contraction of guinea-pig trachea and human airways in a concentration-dependent manner. Glycopyrrolate was more potent than ipratropium bromide. 3. The onset of action (time to attainment of 50% of maximum response) of glycopyrrolate was similar to that obtained with ipratropium bromide in both preparations. In guinea-pig trachea, the offset of action (time taken for response to return to 50% recovery after wash out of the test antagonist) for glycopyrrolate (t1/2 [offset]=26.4+/-0.5 min) was less than that obtained with ipratropium bromide (81.2+/-3.7 min). In human airways, however, the duration of action of glycopyrrolate (t1/2 [offset]>96 min) was significantly more prolonged compared to ipratropium bromide (t1/2 [offset]= 59.2+/-17.8 min). 4. In competition studies, glycopyrrolate and ipratropium bromide bind human peripheral lung and human airway smooth muscle (HASM) muscarinic receptors with affinities in the nanomolar range (K1 values 0.5-3.6 nM). Similar to ipratropium bromide, glycopyrrolate showed no selectivity in its binding to the M1-M3 receptors. Kinetics studies, however, showed that glycopyrrolate dissociates slowly from HASM muscarinic receptors (60% protection against [3H]-NMS binding at 30 nM) compared to ipratropium bromide. 5. These results suggest that glycopyrrolate bind human and guinea-pig airway muscarinic receptors with high affinity. Furthermore, we suggest that the slow dissociation profile of glycopyrrolate might be the underlying mechanism by which this drug accomplishes its long duration of action.

The use of anticholinergics in asthma

Anticholinergic medications have been accepted as an important treatment modality in chronic bronchitis and chronic asthma, but their use in acute asthma is more controversial. A brief historical context of anticholinergics is given. The innervations of the lung that govern bronchoconstriction and bronchodilatation are reviewed. The pharmacological and neurological properties of anticholinergics make them excellent modalities for treatment of asthma. The benefits of anticholinergics in acute asthma, exercise-induced asthma, nocturnal asthma, and psychogenic asthma are reviewed. The use of anticholinergics in anaphylaxis with beta-blockade is examined.

Efficacy of atropine sulfate in combination with albuterol in the treatment for acute asthma

OBJECTIVE

To determine the efficacy of combination therapy using atropine sulfate and albuterol in the treatment for an acute exacerbation of asthma.

METHODS

A prospective, randomized double-blind, placebo-controlled study was performed in the ED of a large, inner-city, university-affiliated teaching hospital. Participants were a convenience sample of patients presenting to the ED between September 1993 and March 1994 with acute exacerbations of their asthma. Patients judged to be in extremis were excluded. All patients received 3 nebulized treatments with 2.5 mg of albuterol at 0, 30, and 60 minutes. Patients were randomized into 1 of 3 groups with the following added to their nebulizer solutions: 1) saline placebo during all 3 treatments; 2) 2.0 mg atropine sulfate added to the first nebulizer and saline in the second and third; or 3) 2.0 mg atropine to the first and third treatments (with saline in the second). No other medication was administered during the study period. At 90 minutes, the patients were evaluated for admission or release from the ED according to predetermined criteria, and additional medications were given as necessary. Vital signs, peak expiratory flow rate (PEFR), degree of wheezing, level of distress, and side effects were measured before and after each nebulizer treatment.

RESULTS

Of the 153 patients eligible for the study, 126 completed the entire study protocol. There was no significant difference between the 3 groups on any parameter studied, including improvement of PEFR, vital signs, or level of distress. There was no difference in the admission rate between the 3 groups, nor was there a difference in the incidence of side effects among the groups.

CONCLUSION

In this study population, combination therapy with atropine sulfate and albuterol offered no significant benefit over the use of albuterol alone in the treatment for acute exacerbation of asthma.

Acute asthma

The number of patients presenting to the emergency department with severe acute asthma exacerbations is increasing. Prompt and aggressive therapy often ameliorates the symptoms and decreases the morbidity and mortality associated with this disease. A directed history and physical examination should be performed, often simultaneously with treatment. The use of inhaled beta-adrenergic agents and the early use of corticosteroids will reverse most attacks. In addition, the use of anticholinergic agents may benefit selected patients. Despite aggressive treatment, some patients will require endotracheal intubation. Controlled intubation with proper sedation and paralysis will decrease the associated morbidity. Complications associated with mechanical ventilation may be prevented by decreasing the amount of auto-PEEP by controlled hypoventilation. Asthma, when incompletely or inadequately treated, can be a rapidly fatal disease process. Conservative approaches to patient admission based on strict objective pulmonary function testing should decrease morbidity and mortality.

Management of severe exacerbations of asthma

Asthma is a common disease that afflicts as many as 5% of Americans. Severe exacerbations of asthma can be life-threatening if not treated aggressively. Despite publication of therapeutic guidelines developed by experts in this field, the clinical management of severe exacerbations of asthma varies widely among institutions and practitioners. This article briefly reviews the pathophysiology of asthma and outlines a systematic, mechanistic approach to treating patients with severe asthma that integrates many clinical advancements made during the past 5 to 10 years.

Effects of combined treatment with glycopyrrolate and albuterol in acute exacerbation of chronic obstructive pulmonary disease

STUDY OBJECTIVE

To investigate whether the addition of a single aerosolized dose of glycopyrrolate leads to a greater improvement in pulmonary function than treatment with albuterol alone for patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective, randomized, blinded, controlled study. Fifty-seven patients with acute exacerbation of COPD were entered into the study. All patients received three aerosol treatments. Patients were randomized to receive 2 mg aerosolized glycopyrrolate (combination therapy group) or aerosolized placebo in addition to their first 2.5-mg albuterol aerosol treatment. All patients received 2.5 mg of aerosolized albuterol alone for the next two treatments.

SETTING

Urban teaching hospital emergency department.

RESULTS

We found no difference in pretreatment 1-second fractional expired volume (FEV1) between the control and glycopyrrolate groups. There was no significant difference in the absolute value of the FEV1 at 1 hour or at 3 hours between the two groups; however, patients who received combination therapy had a greater percent increase from the pretreatment value of FEV1 (56%) as measured in milliliters than did control patients (19%; P = .008).

CONCLUSION

The combination of glycopyrrolate and albuterol produces a greater improvement in FEV1 than does albuterol alone in the treatment of patients with acute exacerbation of COPD.

Effects of combined treatment with glycopyrrolate and albuterol in acute exacerbation of asthma

STUDY OBJECTIVE

Recent reports suggest that glycopyrrolate is as effective as metaproterenol in the treatment of acute bronchospasm. The purpose of this study was to investigate whether the addition of a single aerosolized dose of glycopyrrolate to an albuterol regimen results in a greater improvement in pulmonary function than treatment with an albuterol regimen alone in patients with acute asthma.

DESIGN

Prospective, randomized, double-blinded, controlled study. All patients received a total of three aerosol treatments and 60 mg solumedrol IV push. Patients were randomized to receive 2 mg aerosolized glycopyrrolate (combination therapy) or aerosolized placebo (control) in addition to their first 2.5 mg albuterol aerosol treatment. Both groups received 2.5 mg aerosolized albuterol alone for the next two treatments.

SETTING

An urban teaching hospital emergency department.

PARTICIPANTS

One hundred twenty-five patients with acute exacerbation of asthma were entered into the study.

MAIN RESULTS

There was no difference in pretreatment forced expiratory volume (one second) (FEV1) between the control group and the glycopyrrolate group. Asthmatic patients receiving combination therapy had less of a change in FEV1 (52%) than did control patients (82%, P < .05).

CONCLUSION

The combination of glycopyrrolate and albuterol does not appear to be beneficial over albuterol alone in treating patients with acute exacerbation of asthma.

Effects of short-term inhaled budesonide and beclomethasone dipropionate on serum osteocalcin in premenopausal women

Serum osteocalcin, a marker of bone osteoblast function, has been shown to be sensitive to even low doses of oral glucocorticoids. The effect of 1 wk of inhaled glucocorticoid therapy with budesonide (200 micrograms/puff), beclomethasone dipropionate (250 micrograms/puff), and placebo at two puffs b.i.d. and four puffs b.i.d. on 0900 serum osteocalcin were compared in a double-blind randomized fashion. A two-way repeated-measures analysis of variance showed no main effect of drug or dosage but a significant drug-dose interaction (p = 0.023). Post hoc investigation of this interaction demonstrated that the serum osteocalcin level while taking four puffs b.i.d. (2,000 micrograms) of beclomethasone dipropionate was significantly lower than that of placebo or budesonide at four puffs b.i.d. (1,600 micrograms). These results suggest that at lower doses no acute measurable effect of inhaled glucocorticoids on serum osteocalcin can be appreciated but that at higher doses inhaled beclomethasone dipropionate has a depressant effect on bone osteoblast function.

Glycopyrronium bromide blocks differentially responses mediated by muscarinic receptor subtypes

To analyse the potency of glycopyrronium bromide in blocking responses mediated via subtypes of muscarinic receptors in vitro, we tried to determine its equilibrium dissociation constants at prejunctional muscarinic receptors inhibiting the twitch response of rabbit vas deferens (presumed M1 type), at M2 (paced at left atria), M3 (guinea pig ileum) muscarinic receptor subtypes and at the muscarinic receptor of the rabbit iris sphincter (not M1-M4, not m5). Glycopyrronium bromide shifted to the right the curve for inhibition of the twitch response induced by the agonist McN-A-343, and the methacholine-induced curves for inhibition of rat atrial contraction, and for tonic contraction of guinea pig ileum and rabbit iris sphincter. Glycopyrronium bromide blocked with very high potency (> 11, apparent -log KB) the response in rabbit vas deferens. Its affinity was low (9.09) for the M2 subtype, and intermediate (10.31 or 10.13) for the ileal M3 and the atypical iris muscarinic receptor subtype, respectively. Except at the receptors in rabbit vas deferens, the blockade of agonist effect appeared to be of simple competitive type. In conclusion, glycopyrronium bromide is about 10 or 100 fold more potent in preventing a response to activation of the prejunctional receptor in rabbit vas deferens than in blocking an M3 or M2 muscarinic receptor subtype, respectively, in vitro. The low affinity for M2 receptors may, in part, explain the low incidence of unwanted tachycardia in therapy. The drug failed to discriminate between an M3 receptor and the atypical rabbit iris sphincter receptor.

Emergency Department and Hospital Treatment of Asthma

Asthma is one of the most frequently treated problems in emergency departments and hospitals. Over the last 10 years, several excellent clinical trials have redefined the optimal approach to treating acute, severe asthma. Both in the emergency department and in the hospital, frequent doses of inhaled β2-agonists and systemic corticosteroids are the cornerstones of treatment. In either setting, theophylline therapy adds no or minimal benefits. Inhaled anticholinergics add to the efficacy of the initial dose only of inhaled β2-agonist in the emergency department. Pharmacists should help ensure optimal treatment in acute care settings via protocols as well as routine patient monitoring and drug use evaluation. Improving long-term prevention of asthma should also be addressed by careful patient education and treatment protocols. Serving on a case management team is one excellent approach of helping patients with asthma. Providing pharmaceutical care for asthmatics is a rewarding experience that can dramatically improve clinical outcomes, including a reduced need for emergency and hospital treatment. Copyright © 1992 by W.B. Saunders Company

Treatment of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is an ever present problem in the United States. Characterized by features of both bronchitis and emphysema, the course is generally slow and progressive. However, acute exacerbations do occur, averaging one to four exacerbations per patient per year. These exacerbations, typically characterized by increasing dyspnea, cough, and sputum production, often require immediate treatment. As single agents, both anticholinergic and β-adrenergic agents have been proven effective in acute COPD exacerbations, yet their combination may provide little added therapeutic effect over either agent alone. In light of questionable effectiveness and the potential for toxicity, the role of methylxanthines in the management of COPD has been critically evaluated over the past several years. Certain patients may show improvement from the use of corticosteroids and/or antibiotics during an acute exacerbation; however, these patients are not always easily identifiable. Lastly, patients presenting with a PaO2 < 60 mm Hg will usually benefit from oxygen therapy. This article discusses some of the current views on the efficacy of these various treatments for acute COPD exacerbations.

Correct use of metered-dose inhalers and spacer devices

In addition to prescribing an appropriate drug regimen, physicians must carefully educate asthmatic patients. For 10 million such patients in the United States as well as millions more around the world, successful education is critical to quality of life and can save lives. Responsible patients who understand that asthma attacks are preventable and who use their medications correctly usually have a gratifying response to treatment. Of special importance is the optimal use of aerosolized drugs, most often given by a metered-dose inhaler plus spacer device.

Beta-adrenergic agonists for acute, severe asthma

OBJECTIVE

To critically review the use of beta-adrenergic agonists in acute, severe asthma with particular focus on aerosol administration.

DATA SOURCES

English language articles published since 1971 on the use of beta-agonists for acute asthma. Studies were identified from bibliographies of book chapters, review articles, and other research articles.

STUDY SELECTION

All studies (21 total) comparing systemic with inhaled beta-agonists were reviewed, regardless of their design or outcome. Selected studies highlighting specific aspects of beta-agonist use in acute asthma such as beta-agonists versus other bronchodilators, aerosol delivery, and intravenous beta-agonists were also reviewed.

DATA EXTRACTION

Performed subjectively by the authors with specific aspects of quality discussed within the body of the article.

DATA SYNTHESIS

The beta-agonists provide superior bronchodilation in acute severe asthma compared with either the methylxanthines and/or anticholinergics. The majority of studies found aerosolized beta-agonists to be either as effective as or more effective than parenteral beta-agonists and to produce fewer adverse cardiovascular effects. Studies showing preference for parenteral therapy have either been of poor design or used low doses of an aerosolized beta-agonist. Based on studies of aerosol delivery, there is no advantage of jet nebulization over metered-dose inhalers; however, other aspects, including ease of administration, favor nebulization as the delivery method of choice. The articles recommending intravenous beta-agonists consist of a series of uncontrolled cases.

CONCLUSIONS

Aerosolized selective beta 2-agonists are the bronchodilator treatments of choice for acute, severe asthma. Attention to the details of dosing and delivery are required for optimal results. The final dose and dosing interval are determined by the patient's response. Intravenous beta-agonists are hazardous and cannot be recommended.

Emergency department asthma treatment protocol

OBJECTIVE

The purpose of this study was to determine if a brief educational intervention (INT) on the treatment of acute asthma improved prescribing patterns of internal medicine residents in an emergency department (ED). Additional objectives were to determine if optimal therapy reduced length of stay (LOS) in the ED and to determine if discharge prescribing patterns could be improved.

DESIGN

Nonrandomized, single-blind INT study.

SETTING

A large, urban, county-owned, university-affiliated ED.

PATIENTS AND OTHER PARTICIPANTS

Eight internal medicine residents in each of three study periods; numbers of adult asthmatics for each period were: control group, 129 (Nov-Dec 1989); INT group A, 82 (Jan-Feb 1990); and INT group B, 139 (Nov-Dec 1990).

INTERVENTIONS

INT consisted of a ten-minute verbal presentation, a three-page summary of the literature, and a posted protocol in the ED. Control data were collected prior to any INT. Prescribing patterns were covertly evaluated in each of the three study periods. Because discharge prescribing of long-term antiinflammatory therapy with inhaled corticosteroids was not improved in group A, emphasis on this point was added for group B.

MAIN OUTCOME MEASURES

Percentage of patients who received desired acute and discharge therapies and LOS for each study period.

RESULTS

Increased prescribing of desired acute therapy in the ED was seen in both INT groups. For discharge prescribing, the INT was partially successful. Reduced LOS was not found for the INT groups.

CONCLUSIONS

A brief INT effectively improves prescribing of optimal acute therapy of asthma in the ED, yet does not appear to reduce LOS. Further strategies are needed to impact on therapy prescribed at discharge from the ED.

Asthma in the emergency department: impact of a protocol on optimizing therapy

The objective of this study was to evaluate the impact of a simple educational intervention on the prescribing habits of internal medicine residents in the treatment of acute asthma in a busy emergency department (ED). Prescribing habits for 16 residents were documented for 4 months. The first 2 months served as a control period during which eight residents managed asthma patients without the benefit of any specific educational intervention beyond standard department protocols. A total of 129 patients treated by the residents during this initial phase were assessed. During the second 2-month period, a 10-minute verbal presentation and explicit written treatment protocol were provided to another eight residents, and their treatment of 83 patients was covertly evaluated. Increased prescribing of desired therapy was significantly improved in every area except that of prescribing an inhaled steroid metered dose inhaler for use as a discharge medication. The 10-minute verbal presentation given in conjunction with a three-page handout was found to be highly effective for eliciting improvement in treatment practices during short clinical rotations. The duration of this effect beyond each rotation is unknown. This educational intervention should be presented by the ED medical director, clinical pharmacist, or other appropriate clinician in virtually any ED as quality of patient care can be dramatically improved.