Reduction of nocturnal asthma by an inhaled anticholinergic drug

From sleep medicine to medicine during sleep-a clinical perspective

Objective. In this perspective paper, we aim to highlight the potential of sleep as an auspicious time for diagnosis, management and therapy of non-sleep-specific pathologies.Approach. Sleep has a profound influence on the physiology of body systems and biological processes. Molecular studies have shown circadian-regulated shifts in protein expression patterns across human tissues, further emphasizing the unique functional, behavioral and pharmacokinetic landscape of sleep. Thus, many pathological processes are also expected to exhibit sleep-specific manifestations. Modern advances in biosensor technologies have enabled remote, non-invasive recording of a growing number of physiologic parameters and biomarkers promoting the detection and study of such processes.Main results. Here, we introduce key clinical studies in selected medical fields, which leveraged novel technologies and the advantageous period of sleep to diagnose, monitor and treat pathologies. Studies demonstrate that sleep is an ideal time frame for the collection of long and clean physiological time series data which can then be analyzed using data-driven algorithms such as deep learning.Significance.This new paradigm proposes opportunities to further harness modern technologies to explore human health and disease during sleep and to advance the development of novel clinical applications - from sleep medicine to medicine during sleep.

Frequency of Tiotropium Bromide Use and Clinical Features of Patients with Severe Asthma in a Real-Life Setting: Data from the Severe Asthma Network in Italy (SANI) Registry

Purpose

Patients with uncontrolled asthma despite high doses of inhaled corticosteroid therapy plus another controller are defined as severe asthmatics. Tiotropium bromide respimat (TBR) is the only long-acting muscarinic antagonists (LAMA) approved for severe asthma. The aim of this study was to explore the frequency of severe asthmatics treated with TBR and characterize their clinical features in a real-life, registry-based setting.

Materials and Methods

Baseline data from the Severe Asthma Network in Italy (SANI) registry have been analyzed to determine the use of TBR and other LAMA, and to compare clinical, functional and inflammatory features associated with the use of LAMA.

Results

Among a total of 698 enrolled patients, 35.9% were treated with LAMA (23.3% TBR, 4.5% tiotropium bromide handihaler, 4.5% aclidinium, 3.4% glycopyrronium bromide 0.3% umeclidinium bromide). Age of asthma onset was higher in patients taking LAMA, whom, compared to others were more frequently former smokers. They also had a higher annual exacerbation rate, experienced worst asthma control, worst disease-related quality of life and poorer lung function. Bronchiectasis was more frequently found in LAMA users (25.9% vs 13.1%).

Conclusion

TBR is still underused in severe asthma in a real-life setting, while a relevant proportion of patients are treated with other LAMA that are not approved for severe asthma treatment. Patients taking LAMA have features characteristic of even more severe asthma.

Therapeutics on the clock: Circadian medicine in the treatment of chronic inflammatory diseases

The circadian clock is a collection of endogenous oscillators with a periodicity of ~ 24 h. Recently, our understanding of circadian rhythms and their regulation at genomic and physiologic scales has grown significantly. Knowledge of the circadian influence on biological processes has provided new possibilities for novel pharmacological strategies. Directly targeting the biological clock or its downstream targets, and/or using timing as a variable in drug therapy are now important pharmacological considerations. The circadian machinery mediates many aspects of the inflammatory response and, reciprocally, an inflammatory environment can disrupt circadian rhythms. Therefore, intense interest exists in leveraging circadian biology as a means to treat chronic inflammatory diseases such as sepsis, asthma, rheumatoid arthritis, osteoarthritis, and cardiovascular disease, which all display some type of circadian signature. The purpose of this review is to evaluate the crosstalk between circadian rhythms, inflammatory diseases, and their pharmacological treatment. Evidence suggests that carefully rationalized application of chronotherapy strategies - alone or in combination with small molecule modulators of circadian clock components - can improve efficacy and reduce toxicity, thus warranting further investigation and use.

[The problem of obstructive sleep apnea syndrome in asthmatic patients]

Asthma and obstructive sleep apnea syndrome (OSAS) are one of the most common chronic respiratory diseases. These have common risk factors that include obesity, gastroesophageal reflux disease (GERD) and impaired nasal breathing (allergic rhinitis, sinusitis). At the same time, experimental evidence demonstrates common pathophysiological mechanisms of these diseases, such as involvement in the process of the respiratory tract, a systemic inflammatory response, and implementation of neuromechanical reflexes. Thus, there is an obvious synergism between these conditions, which affects symptoms, response to therapy, and prognosis. The available data allow discussion on whether there is a need to identify and treat OSAS in asthmatic patients. By keeping in mind the high incidence of OSAS in patients with severe asthma, it may be suggested that treatment for OSAS can reduce the number of exacerbations, improve the quality of life, and decline the number of obstinate asthma cases. It is very important for general practitioners to assess risk factors, such as body weight, nasal stuffiness, and GERD, and to utilize screening tools for more efficient use of healthcare resources. Considering the known positive effects of CPAP therapy in short-term studies, future investigations should focus on the impact of CPAP therapy on asthma symptoms in the long-term, as well as on the effects of asthma drugs on the course of OSAS.

The Role of the Body Clock in Asthma and COPD: Implication for Treatment

Asthma exhibits a marked time of day variation in symptoms, airway physiology, and airway inflammation. This is also seen in chronic obstructive pulmonary disease (COPD), but to a lesser extent. Our understanding of how physiological daily rhythms are regulated by the circadian clock is increasing, and there is growing evidence that the molecular clock is important in the pathogenesis of these two airway diseases. If time of day is important, then it follows that treatment of asthma and COPD should also be tailored to the most efficacious time of the day, a concept known as 'chronotherapy'. There have been a number of studies to determine the optimal time of day at which to take medications for asthma and COPD. Some of these agents are already used 'chronotherapeutically' in practice (often at night-time). However, several studies investigating systemic and inhaled corticosteroids have consistently shown that the best time of day to take these medications for treating asthma is in the afternoon or early evening and not in the morning, when these medications are often prescribed. Future, large, randomized, placebo-controlled studies of systemic and inhaled corticosteroids in asthma and COPD are needed to inform clinical practice.

The Role of the Body Clock in Asthma and COPD: Implication for Treatment

Asthma exhibits a marked time of day variation in symptoms, airway physiology, and airway inflammation. This is also seen in chronic obstructive pulmonary disease (COPD), but to a lesser extent. Our understanding of how physiological daily rhythms are regulated by the circadian clock is increasing, and there is growing evidence that the molecular clock is important in the pathogenesis of these two airway diseases. If time of day is important, then it follows that treatment of asthma and COPD should also be tailored to the most efficacious time of the day, a concept known as ‘chronotherapy’. There have been a number of studies to determine the optimal time of day at which to take medications for asthma and COPD. Some of these agents are already used ‘chronotherapeutically’ in practice (often at night-time). However, several studies investigating systemic and inhaled corticosteroids have consistently shown that the best time of day to take these medications for treating asthma is in the afternoon or early evening and not in the morning, when these medications are often prescribed. Future, large, randomized, placebo-controlled studies of systemic and inhaled corticosteroids in asthma and COPD are needed to inform clinical practice.

Digital Features

This article is published with a graphical abstract to facilitate understanding of the article. To view digital features for this article go to the Supplementary Information of the article.

Sleep in asthma

Many patients with asthma experience worsening of symptoms at night. Understanding the mechanism of nocturnal asthma and the factors that exacerbate asthma during sleep would lead to better management of the condition.

Autonomic neural control of intrathoracic airways

Autonomic neural control of the intrathoracic airways aids in optimizing air flow and gas exchange. In addition, and perhaps more importantly, the autonomic nervous system contributes to host defense of the respiratory tract. These functions are accomplished by tightly regulating airway caliber, blood flow, and secretions. Although both the sympathetic and parasympathetic branches of the autonomic nervous system innervate the airways, it is the later that dominates, especially with respect to control of airway smooth muscle and secretions. Parasympathetic tone in the airways is regulated by reflex activity often initiated by activation of airway stretch receptors and polymodal nociceptors. This review discusses the preganglionic, ganglionic, and postganglionic mechanisms of airway autonomic innervation. Additionally, it provides a brief overview of how dysregulation of the airway autonomic nervous system may contribute to respiratory diseases.

Cardiac asthma: new insights into an old disease

Cardiac asthma has been defined as wheezing, coughing and orthopnea due to congestive heart failure. The clinical distinction between bronchial asthma and cardiac asthma can be straight forward, except in patients with chronic lung disease coexisting with left heart disease. Pulmonary edema and pulmonary vascular congestion have been thought to be the primary causes of cardiac asthma but most patients have a poor response to diuretics. There appears to be limited effectiveness of classical asthma medications like bronchodilators or corticosteroids in treating cardiac asthma. Evidence suggests that circulating inflammatory factors and tissue growth factors also lead to airway obstruction suggesting the possibility of developing novel therapies.

Increased vagal airway tone in fatal asthma

Slow-onset asthma deaths are characterized by eosinophilic airway infiltrates and thickening of the basal membrane, while rapid-onset asthma deaths are associated with fewer airway inflammatory changes, suggesting that bronchospasm may be responsible for the latter events. Airway tone is primarily controlled by the autonomous nervous system and can be pharmacologically modified. Therapies that stimulate the sympathetic beta(2) adrenoreceptor or inhibit the muscarinic receptor signal transduction induce bronchodilation. Parasympathetic (vagal) airway tone is enhanced in some asthmatics due to a number of stimuli, while in others it is constitutively heightened. Mainstream asthma therapy, however, only consists of corticosteroids and beta(2) agonists, not addressing this aspect. In this publication, I propose that increased vagal airway tone resulting in overwhelming bronchoconstriction and mucus plugging could be responsible for the near-fatal or fatal events observed in a number of asthmatics, in spite of their adequate treatment with standard therapies. On the basis of this hypothesis, I recommend that vagal airway tone be assessed in all patients with asthma, particularly in those with a history of near-fatal events. If the airway tone is increased, individuals should be treated with a triple combination of long-acting beta(2) agonists, inhaled steroids, and inhaled anticholinergics to prevent vagally mediated fatal events.

Chronobiology and chronotherapy of allergic rhinitis and bronchial asthma

Study of the chronobiology of allergic rhinitis (AR) and bronchial asthma (BA) and the chronopharmacology and chronotherapy of the medications used in their treatment began five decades ago. AR is an inflammatory disease of the upper airway tissue with hypersensitivity to specific environmental antigens, resulting in further local inflammation, vasomotor changes, and mucus hypersecretion. Symptoms include sneezing, nasal congestion, and runny and itchy nose. Approximately 25% of children and 40% of adults in USA are affected by AR during one or more seasons of the year. The manifestation and severity of AR symptoms exhibit prominent 24-h variation; in most persons they are worse overnight or early in the morning and often comprise nighttime sleep, resulting in poor daytime quality of life, compromised school and work performance, and irritability and moodiness. BA is also an inflammatory medical condition of the lower airways characterized by hypersensitivity to specific environmental antigens, resulting in greater local inflammation as well as bronchoconstriction, vasomotor change, and mucus hypersecretion. In USA an estimated 6.5 million children and 15.7 million adults have BA. The onset and worsening of BA are signaled by chest wheeze and/or croupy cough and difficult and labored breathing. Like AR, BA is primarily a nighttime medical condition. AR is treated with H1-antagonist, decongestant, and anti-inflammatory (glucocorticoid and leukotriene receptor antagonist and modifier) medications. Only H1-antagonist AR medications have been studied for their chronopharmacology and potential chronotherapy. BA is treated with some of the same medications and also theophylline and beta2-agonists. The chronopharmacology and chronotherapy of many classes of BA medications have been explored. This article reviews the rather extensive knowledge of the chronobiology of AR and BA and the chronopharmacology and chronotherapy of the various medications used in their treatment.

The development of anticholinergics in the management of COPD

Anticholinergics have been used to treat obstructive respiratory disease for many years from historical preparations of the deadly nightshade genus, to the more recent developments ofipratropium, oxitropium, and tiotropium. The medical treatment of airways obstruction has focused on achieving maximal airway function through bronchodilators. Of the two main bronchodilators, beta2-agonists are often the first treatment choice although there is evidence of equivalence and some suggestions of the superiority of anticholinergics in chronic obstructive pulmonary disease (COPD). The following review looks at the background of anticholinergics, their pharmacological properties, and the evidence for use with suggestions for their place in the treatment of COPD.

CNS determinants of sleep-related worsening of airway functions: implications for nocturnal asthma

This review summarizes the recent neuroanatomical and physiological studies that form the neural basis for the state-dependent changes in airway resistance. Here, we review only the interactions between the brain regions generating quiet (non-rapid eye movement, NREM) and active (rapid eye movement, REM) sleep stages and CNS pathways controlling cholinergic outflow to the airways. During NREM and REM sleep, bronchoconstrictive responses are heightened and conductivity of the airways is lower as compared to the waking state. The decrease in conductivity of the lower airways parallels the sleep-induced decline in the discharge of brainstem monoaminergic cell groups and GABAergic neurons of the ventrolateral periaqueductal midbrain region, all of which provide inhibitory inputs to airway-related vagal preganglionic neurons (AVPNs). Withdrawal of central inhibitory influences to AVPNs results in a shift from inhibitory to excitatory transmission that leads to an increase in airway responsiveness, cholinergic outflow to the lower airways and consequently, bronchoconstriction. In healthy subjects, these changes are clinically unnoticed. However, in patients with bronchial asthma, sleep-related alterations in lung functions are troublesome, causing intensified bronchopulmonary symptoms (nocturnal asthma), frequent arousals, decreased quality of life, and increased mortality. Unquestionably, the studies revealing neural mechanisms that underlie sleep-related alterations of airway function will provide new directions in the treatment and prevention of sleep-induced worsening of airway diseases.

Nocturnal asthma: underlying mechanisms and treatment

Nocturnal asthma is defined by a drop in forced expiratory volume in 1 second (FEV(1)) of at least 15% between bedtime and awakening in patients with clinical and physiologic evidence of asthma. Nocturnal symptoms are a common part of the asthma clinical syndrome; up to 75% of asthmatics are awakened by asthma symptoms at least once per week, and approximately 40% experience nocturnal symptoms on a nightly basis. An extensive body of research has demonstrated that nocturnal symptoms such as cough and dyspnea are accompanied by increases in airflow limitation, airway hyperresponsiveness, and airway inflammation. Treatment strategies in nocturnal asthma are similar to those used in persistent asthma, although dosing of medications to target optimum delivery during periods of nocturnal worsening is beneficial.

Chronic obstructive pulmonary disease and community-based pharmacological care

Chronic obstructive pulmonary disease carries a high morbidity and mortality and is one of the few chronic diseases where the number of people affected is rising, a trend that looks set to continue. Unfortunately patients often present at a late stage of the disease when therapeutic options are more limited and many patients are undertreated, overtreated or misdiagnosed. While patients present both in primary and secondary care it is primary care where the majority of patients are managed and where patients are likely to be seen at an earlier stage of the disease process when interventions are likely to be more effective. Therapeutic options for patients with COPD include pharmacological approaches and these should be prescribed on an individual basis and both subjective and objective criteria used in evaluating effectiveness.

Anticholinergic agents for chronic asthma in adults

BACKGROUND

Anticholinergic agents such as ipratropium bromide are sometimes used in the treatment of chronic asthma. They effect bronchodilation and have also been used in combination with beta2-agonists in the management of chronic asthma.

OBJECTIVES

To examine the effectiveness of anticholinergic agents versus placebo and in comparison with beta2-agonists or as adjunctive therapy to beta2-agonists.

SEARCH STRATEGY

The Cochrane Airways Group asthma and wheeze database was searched with a pre-defined search strategy. Searches were current as of August 2003. Reference lists of articles were also examined.

SELECTION CRITERIA

Randomised trials or quasi-randomised trials were considered for inclusion. Studies assessing an anticholinergic agent versus placebo or in combination/comparison with beta2-agonists were included. In practice, all beta2-agonists were short acting. Short-term (less than 24 hours duration) and longer-term studies were separated; the latter are reported in this review and the former in the review, "Anticholinergic agents for chronic asthma in adults short term".

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed abstracts for retrieval of full text articles. Papers were then assessed for suitability for inclusion in the review. Data from included studies were extracted by two reviewers and entered into the software package (RevMan 4.2). We contacted authors for missing data and some responded. Adverse effect data were analysed if reported in the included studies.

MAIN RESULTS

The studies analysed were in two groups: those comparing anticholinergics with placebo and those comparing the combination of anticholinergics with short acting beta2-agonists versus short acting beta2-agonists alone. The former group had 13 studies involving 205 participants included in this review, and the latter 9 studies involving 440 patients. Generally methodological quality was poorly reported, and there were some reservations with respect to the quality of the studies. Despite the limited number of studies that could be combined, anticholinergic agents in comparison with placebo resulted in more favourable symptom scores particularly in respect of daytime dyspnoea (WMD -0.09 (95%CI -0.14, -0.04, 3 studies, 59 patients). Daily peak flow measurements also showed a statistically significant improvement for the anticholinergic (e.g. morning PEF: WMD =14.38 litres/min (95%CI 7.69, 21.08; 3 studies, 59 patients). However the clinical significance is small and in terms of peak flow measurements equates to approximately a 7% increase over placebo. The more clinically relevant comparison of a combination of anticholinergic plus short acting beta2-agonist versus short acting beta2-agonist alone gave no evidence in respect of symptom scores or peak flow rates of any significant differences between the two regimes. Again there are reservations with respect to the quality of the information from which these conclusions are drawn.

REVIEWERS' CONCLUSIONS

Overall this review provides no justification for routinely introducing anticholinergics as part of add-on treatment for patients whose asthma is not well controlled on standard therapies. This does not exclude the possibility that there may be a sub-group of patients who derive some benefit and a trial of treatment in individual patients may still be justified. The role of long term anticholinergics such as tiotropium bromide has yet to be established in patients with asthma and any future trials might draw on the messages derived from this review.

Effect of tiotropium bromide on circadian variation in airflow limitation in chronic obstructive pulmonary disease

BACKGROUND

In chronic obstructive pulmonary disease (COPD), the degree of circadian variation in forced expiratory volume in 1 second (FEV1) and the influence of anticholinergic blockade is not known. Tiotropium is a long acting inhaled anticholinergic bronchodilator that increases daytime FEV1 in COPD. We hypothesised that tiotropium would modify the overnight change in FEV1, and this would be unaffected by the timing of drug administration.

METHODS

A double blind, randomised, placebo controlled trial was conducted with tiotropium 18 mg once daily in the morning (09.00 hours), evening (21.00 hours), or an identical placebo. Patients with stable COPD (n=121, FEV1=41% predicted) underwent spirometric tests every 3 hours for 24 hours at baseline and after 6 weeks of treatment.

RESULTS

There were no significant differences at baseline between the groups. Tiotropium improved mean (SE) FEV1 (over 24 hours) in the morning (1.11 (0.03) l) and evening (1.06 (0.03) l) groups compared with placebo (0.90 (0.03) l), and nocturnal FEV1 (mean of 03.00 and 06.00 hours) in the morning (1.03 (0.03) l) and evening (1.04 (0.03) l) groups compared with placebo (0.82 (0.03) l) at the 6 week visit (p<0.01). FEV1 before morning or evening dosing was similar, while the peak FEV1 moved later in the day with active treatment. The mean percentage change in FEV1 from 09.00 hours to 03.00 hours (the nocturnal decline in FEV1) was -2.8% in the morning group, -1.0% in the evening group, and -12.8% in the placebo group. The magnitude of the peak to trough change in FEV1 was not statistically different.

CONCLUSIONS

Tiotropium produced sustained bronchodilation throughout the 24 hour day without necessarily abolishing circadian variation in airway calibre.

Underdiagnosed asthma in South Australia

BACKGROUND

The prevalence of undiagnosed asthma in the general population and the clinical and demographic characteristics of these patients compared with those with diagnosed asthma are unclear.

METHODS

The North West Adelaide Health Survey (NWAHS) is a population household interview survey of adults (age>18 years) in the north western suburbs of Adelaide, South Australia (regional population 0.6 million). Data obtained were weighted to the closest census data to provide population representative estimates. Positive answers to: "Have you ever had asthma?"; "Has it been confirmed by a doctor?"; "Do you still have asthma?" determined current physician diagnosed asthma. A positive bronchodilator response on spirometric testing according to ATS criteria without a physician's diagnosis determined undiagnosed asthma. Other measures included the SF-12 health survey questionnaire, the Selim index of severity of chronic lung disease, skin allergy tests, and demographic data.

RESULTS

Of the 3422 individuals interviewed, 2523 (74%) agreed to participate in the clinical assessment. Of these, 292 (11.6%) had asthma, 236 (9.3%) with a doctor's diagnosis of asthma and 56 (2.3%) with undiagnosed asthma defined on spirometric criteria; thus, 19.2% of the total asthma group were undiagnosed. Those undiagnosed were more likely (p<0.05) to be >40 years old, on government benefits, with an income <AUD$40,000. Symptom frequency was similar in the two asthma groups, but mean spirometric values were lower in the undiagnosed group (p<0.05) while positive skin allergy tests were more common in the diagnosed group (p<0.05). SF-12 component summary scores were significantly lower in both asthma groups than in the non-asthma population. Undiagnosed asthma was frequent in men and in those aged >65 years. Health service use over the previous year was similar for both asthma groups.

CONCLUSION

Undiagnosed asthma is common among the Australian population, with a similar clinical spectrum to those with diagnosed asthma.

Adenosine 5'-triphosphate axis in obstructive airway diseases

In recent years, significant progress has been made in our understanding of the pathophysiology behind obstructive airway diseases in general and asthma in particular; this knowledge, however, has not translated to major breakthroughs in the treatment of these disorders. Current therapeutic options are less than optimal and frequently are associated with systemic adverse effects. Recent studies indicate that endogenous purine nucleotides, adenosine 5'-triphosphate (ATP) in particular, could play a mechanistic role in obstructive airway diseases through their actions on multiple cell types relevant to these disorders, including mast cells, eosinophils, dendritic cells, and neurons. The pharmacologic modulation of ATP signal transduction in these cells represents an attractive new therapeutic target.

Circadian rhythm in peak expiratory flow: alteration with nocturnal asthma and theophylline chronotherapy

We investigated changes in the circadian rhythm of peak expiratory flow (PEF) in seven persons with nocturnal asthma for a 24h span when (1) they were symptom free and their disease was stable, (2) their asthma deteriorated and nocturnal symptoms were frequent, and (3) they were treated with theophylline chronotherapy. Subjects recorded their PEF every 4h between 07:00 and 23:00 one day each period. Circadian rhythms in PEF were assessed using the group-mean cosinor method. The circadian rhythm in PEF varied according to asthma severity. Significant circadian rhythms in PEF were detected during the period when asthma was stable and when it was unstable and nocturnal symptoms were frequent. When nocturnal symptoms were present, the bathyphase (trough time) of the PEF rhythm narrowed to around 04:00; during this time of unstable asthma, the amplitude of the PEF pattern increased 3.9-fold compared to the symptom-free peiiod. No significant group circadian rhythm was detected during theophylline chronotherapy. Evening theophylline chronotherapy proved to be prophylactic for persons whose symptoms before treatment had occurred between midnight and early morning. Changes in the characteristics of the circadian rhythm of PEF, particularly amplitude and time of bathyphase, proved useful in determining when to institute theophylline chronotherapy to avert nocturnal asthma symptoms.

Defecation-induced bronchospasm

Acute asthma exacerbations are common. Patients with asthma experience symptoms in response to a wide variety of stimuli, and identifying the precipitating cause may be useful in guiding treatment and preventing future attacks. A case of asthma exacerbation occurring during multiple defecations is reported. Abnormal parasympathetic tone has been implicated in the pathogenesis of certain types of asthma, and defecation can be associated with increased parasympathetic tone. This patient's pattern of defecation-related asthma exacerbations responded to prophylactic anticholinergic medication.

Airway-parenchyma uncoupling in nocturnal asthma

Airway flow resistance is well known to be dependent upon lung volume. The rise in lung volume that occurs in asthma is therefore thought to be an important mechanism that defends airway patency. The purpose of the current study was to investigate the interdependence or mechanical coupling between airways and lung parenchyma during the inflammatory processes that occur in the patient with nocturnal asthma. Five patients with documented nocturnal asthma were studied in both a vertical and a horizontal body plethysmograph. Lung volume was altered with continuous negative pressure as applied to the chest wall with a poncho cuirass in different postures and during sleep. We found during the awake phase that an increase in lung volume decreased lower pulmonary resistance (Rlp); however, within 30 min of sleep onset, functional residual capacity (FRC) fell and Rlp rose more than would be expected for the fall in FRC. Restoring FRC to presleep values either at an early (half-hour) or a late (3-h) time point did not cause Rlp to significantly fall. A second phase of the study showed that the loss of Rlp dependence on lung volume was not due to the assumption of the supine posture. Indirect measurements of lung compliance were consistent with a stiffening of the lung. We conclude that with sleep there is an immediate uncoupling of the parenchyma to the airway, resulting in a loss of interdependence that persists throughout sleep and may contribute to the morbidity and mortality associated with nocturnal asthma.

Location of airway inflammation in asthma and the relationship to circadian change in lung function

Nocturnal asthma is an important part of asthma as the majority of patients with asthma have nocturnal worsening in lung function. The etiology of this process is multifactorial and interactive. There are many naturally occurring circadian rhythms, which for the normal individual have only a minor effect on lung function. However, in the asthmatic patient, these day-to-night alterations produce increased airway inflammation and worsening of asthma. Although asthma is considered an airway disease, the location of the inflammatory response may be greater in the alveolar tissue area. If correct, this could alter the therapeutic approach to this disease.

Circadian rhythms in the pharmacokinetics and clinical effects of beta-agonist, theophylline, and anticholinergic medications in the treatment of nocturnal asthma

Published asthma consensus reports now acknowledge that asthma is a nocturnal disease in as many as 75% of those afflicted by this medical condition. Nonetheless, the treatment of this chronic obstructive pulmonary disease in the clinic continues to be based primarily on homeostatic considerations in that it relies on long-acting bronchodilator and other therapies formulated and scheduled to ensure constant or near-constant levels of medication during the 24h. The need of asthma patients prone to nighttime attacks is not the same during the day and night; the therapeutic requirements of patients who experience nocturnal asthma, especially ones with the more severe forms of the disease, are often not satisfied by conventional medications. The therapeutic response and patient tolerance to bronchodilator medications can be improved markedly when the medications are proportioned during the 24h as a chronotherapy, that is, when more medication is delivered during nighttime sleep than daytime activity, as verified by numerous studies. This article reviews how the body's circadian rhythms influence the pharmacokinetics and effects of commonly prescribed asthma therapies and addresses why and how they must be taken into consideration to increase the effectiveness of asthma treatment.

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.

Tiotropium bromide (Ba 679 BR), a novel long-acting muscarinic antagonist for the treatment of obstructive airways disease

Tiotropium bromide (Ba 679 BR) is a novel potent and long-lasting muscarinic antagonist that has been developed for the treatment of chronic obstructive airways disease (COPD). Binding studies with [3H]tiotropium bromide in human lung have confirmed that this is a potent muscarinic antagonist with equal affinity for M1-, M2- and M3-receptors and is approximately 10-fold more potent than ipratropium bromide. Tiotropium bromide dissociates very slowly from lung muscarinic receptors compared with ipratropium bromide. In vitro tiotropium bromide has a potent inhibitory effect against cholinergic nerve-induced contraction of guinea-pig and human airways, that has a slower onset than atropine or ipratropium bromide. After washout, however, tiotropium bromide dissociates extremely slowly compared with the dissociation of atropine and ipratropium bromide. Measurement of acetylcholine (ACh) release from guinea-pig trachea shows that tiotropium bromide, ipratropium bromide and atropine all increase ACh release on neural stimulation and that this effect is washed out equally quickly for the three antagonists. This confirms binding studies to transfected human muscarinic receptors which suggested that tiotropium bromide dissociates slowly from M3-receptors (on airway smooth muscle) but rapidly from M2 autoreceptors (on cholinergic nerve terminals). Clinical studies with inhaled tiotropium bromide confirm that it is a potent and long-lasting bronchodilator in COPD and asthma. Furthermore, it protects against cholinergic bronchoconstriction for > 24 h. This suggests that tiotropium bromide will be a useful bronchodilator, particularly in patients with COPD, and may be suitable for daily dosing. The selectivity for M3- over M2-receptors may also confer a clinical advantage.

Sleep in asthma

The nocturnal worsening of asthma is a major cause of morbidity and mortality from this disease. The physiologic changes that occur during normal sleep can have adverse effects on breathing patterns, arousal responses, and airway clearance in asthmatics. Understanding of these alterations in airway mechanics and airway inflammation may lead to better management of this disease.

Effects of inhaled salmeterol and salbutamol (albuterol) on morning dips compared in intensive care patients recovering from an acute severe asthma attack

OBJECTIVE

To assess the effect of a long-acting inhaled beta 2-agonist, salmeterol (SM), compared to a short-acting inhaled beta 2-agonist, salbutamol (or albuterol, SB) on the occurrence of morning dip (MD) in patients recovering from an acute severe asthma attack (ASA).

DESIGN

Prospective study.

SETTING

18-bed, medical intensive care unit (ICU) in a university hospital.

PATIENTS

19 patients suffering from an ASA.

INTERVENTIONS

Serial measurements of the peak expiratory flow rate (PEFR), arterial blood gases, vital capacity and forced expiratory volume in one second (FEV1) were performed from admission. All patients were first treated with i.v. methyl prednisolone and i.v. SB. Once the PEFR was stable and > 35% of predicted value, i.v. SB was stopped while i.v. steroids were maintained, and patients were randomised to either inhaled SB (9 patients, 400 micrograms every 4 h) or inhaled SM (10 patients, 100 micrograms every 12 h).

RESULTS

The mean admission PEFR was 26.1 +/- 11.7% of the predicted value and was not different between the two groups. MD was more frequent with SB (6/9 patients) than with SM (4/10). The severity of MD, expressed in l/min fall in PEFR, was higher in SB than in SM (106 +/- 25 vs 55 +/- 37; p < 0.05).

DISCUSSION

MD is frequent in ASA. In ASA, SM appears to reduce the frequency and the severity of MD more than SB. The clinical implications of this observation, particularly a lowering of mortality and a shortening of the ICU stay, remain to be investigated.

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.

Obstructive sleep apnea syndrome and bronchial hyperreactivity

This study was designed to investigate the prevalence of bronchial hyperreactivity (BH) in patients with obstructive sleep apnea syndrome (OSAS), heavy snorers, and light snorers; its correlation with OSAS severity; and its response to nasal CPAP therapy. Forty-eight age- and sex-matched subjects were selected on the basis of preentry sleep studies: Group I consisted of 16 patients with OSAS (hypopnea-apnea index (HAI) = 35 +/- 9); group II consisted of 16 cases of heavy snorers without OSAS; and group III, a control group, consisted of 16 subjects with only mild snoring. All 48 patients had normal pulmonary function (simple spirometry) prior to study entry and had no history of asthma or allergies. The prevalence of BH was prospectively assessed by giving each subject a methacholine challenge test (MCT). Patients with a positive MCT were treated with 2-3 months of nasal CPAP treatment, after which they had a second MCT. Four of 16 patients in group I had BH on MCT (PD20 = 88, 103, 109, 162 D.U.), whereas none of the group II or III subjects demonstrated BH. There was no correlation between BH and the severity of the OSAS. The 4 patients with BH in group I showed an increase in PD20M after 2-3 months of nasal CPAP treatment. In conclusion, BH may occur in patients with OSAS. It is unrelated to the severity of the OSAS, and nasal constant positive airway pressure (CPAP) therapy can decrease the hyperreactivity to methacholine in these patients.

Effect of long term treatment with oxitropium bromide on airway secretion in chronic bronchitis and diffuse panbronchiolitis

BACKGROUND

Anticholinergic bronchodilator drugs improve lung function in chronic bronchitis but less is known of their effects on the volume and physical properties of sputum in conditions associated with excessive airway secretions. This study examines the effects of the regular use of oxitropium bromide in such patients.

METHODS

The study was conducted in a parallel, double blind, placebo controlled fashion. Patients were divided into two groups: the first group (n = 17) received oxitropium bromide from a metered dose inhaler (two puffs three times daily; 100 micrograms/puff) for eight weeks, and the second group (n = 16) received placebo. Lung function was measured as forced expiratory volume in one second (FEV1) and vital capacity. In evaluating airway secretion, daily amount of expectorated sputum, percentage solid composition, viscoelastic properties including elastic modulus and dynamic viscosity, and sputum microbiology were determined.

RESULTS

Oxitropium bromide increased FEV1 and decreased the mean (SE) sputum production from 61(4) to 42(3) g/day after treatment, whereas placebo had no effect. Bacterial density and sputum flora were unchanged, but solid composition and elastic modulus increased from 2.52(0.43)% to 3.12(0.34)%, and 68(12) dyne/cm2, respectively, in the group taking oxitropium bromide.

CONCLUSIONS

Regular treatment with oxitropium bromide not only improves airflow limitation but also reduces sputum production, probably through the inhibition of both mucus secretion and water transport, the latter component being predominant.

Aetiology of asthma: lessons from lung transplantation

Asthma is thought to result from both genetic and environmental influences. The genetic component is most obviously seen in patients who are atopic and have allergic responses to common antigens. We have done lung transplants in two such patients; and we have also transplanted the lungs from two mildly asthmatic patients, whose death was unrelated to their asthma, into two patients with end-stage cystic fibrosis and primary pulmonary hypertension, respectively. The non-asthmatic recipients of asthmatic lungs developed asthma after transplantation; however, the asthmatic recipients of normal lungs have not developed asthma up to three years after transplantation. These observations support the notion that asthma is a "local" disease.

Terbutaline controlled-release tablets and ipratropium aerosol in nocturnal asthma

The effect of oral terbutaline (controlled-release [CR] tablets) was compared with that of inhaled ipratropium bromide (aerosol) in 21 patients with nocturnal asthma. In a randomized, double-blind, crossover study, the patients were treated with terbutaline CR 10 mg twice daily, ipratropium 40 micrograms four times daily, and the two drugs in combination. Each treatment was given for 3 weeks. Before the start of the study, the patients participated in a 1-week run-in period. The mean nocturnal decline in peak expiratory flow rate (PEFR) was 29% in the run-in period and was reduced to 22% in the terbutaline CR period, 27% in the ipratropium period, and 23% in the period with the combination of the two drugs. The mean night PEFR was significantly (P < 0.05) higher in the period with terbutaline CR, as compared with the period with ipratropium. The mean morning PEFR was also highest in the terbutaline CR period. The mean evening PEFR was significantly (P < 0.05) higher during treatment with terbutaline CR alone and with the combination, as compared with treatment with ipratropium alone. Treatment with terbutaline CR alone or the combination was preferred by as many patients as was treatment with ipratropium alone. When present, adverse reactions were judged to be mild or moderate. Treatment with terbutaline CR alone and the combination significantly improved the evening and night PEFR, as compared with treatment with ipratropium alone.

Treatment of nocturnal asthma with pulsed-release albuterol

The treatment of nocturnal asthma remains a challenge. We investigated the use of a pulsed-released albuterol in ten patients with nocturnal symptoms of asthma. In a randomized, double-blind, placebo-controlled, crossover designed study, we tested the use of 8 mg of pulsed-release albuterol sulfate (Proventil Repetabs) vs placebo. The pulsed-release albuterol significantly blunted the overnight drop in FEV1, improved peak flow readings in the morning, and decreased subjective awakenings from sleep. We conclude that pulsed-released albuterol is an effective therapeutic option in patients with nocturnal asthma.

Spectral analysis of heart rate variability in bronchial asthma

Sympathetic and parasympathetic activity was evaluated in ten healthy controls, nine asymptomatic, untreated asthmatic subjects and ten asthmatic patients during treatment for acute asthma, by measurement of the variation in resting heart rate using frequency spectrum analysis. Heart rate was recorded by ECG and respiratory rate by impedance plethysmography. Spectral density of the beat-to-beat heart rate was measured within the low frequency band 0.04 to 0.10 Hz (low frequency power) modulated by sympathetic and parasympathetic activity, and within a 0.12 Hz band width at the respiratory frequency mode (respiratory frequency power) modulated by parasympathetic activity. Acute asthmatics had higher heart rates than either of the other two groups; this was probably related to the effects of beta-adrenoceptor agonist medication. Sympathetically mediated heart rate variability (normalized low frequency power) was significantly lower in both asymptomatic (p less than 0.002) and acute (p less than 0.02) asthma subjects compared to controls. This is consistent with altered sympathetic/parasympathetic regulation of heart rate in subjects with bronchial asthma.

Brief report: therapeutic manipulations in severe nocturnal asthma. A nonconventional approach in a severe high-risk asthmatic

A patient with severe nocturnal asthma of multifactorial pathogenesis with high-risk features leading to several episodes of nocturnal respiratory arrests is described. Despite aggressive conventional therapy with bronchodilators and glucocorticoid agents, the patient had progressive worsening within the year prior to admission. After a nonconventional approach consisting of: high-dose inhaled steroids, afternoon dose of prednisone, addition of troleandomycin therapy, high-dose inhaled ipratropium at bedtime, maximizing serum theophylline concentrations in the early morning, and nasal CPAP through the night; the patient's pulmonary functions were optimized with minimal or no reduction in morning FEV1, and decreased airways hyperresponsiveness to methacholine.

Salmeterol in nocturnal asthma: a double blind, placebo controlled trial of a long acting inhaled beta 2 agonist

OBJECTIVE

To determine whether inhaled salmeterol, a new long acting inhaled beta adrenergic agonist, reduces nocturnal bronchoconstriction and improves sleep quality in patients with nocturnal asthma.

DESIGN

Randomised, double blind, placebo controlled crossover study.

SETTING

Hospital outpatient clinics in Edinburgh.

SUBJECTS

Twenty clinically stable patients (13 women, seven men) with nocturnal asthma, median age 39 (range 18-60) years.

INTERVENTIONS

Salmeterol 50 micrograms and 100 micrograms and placebo taken each morning and evening by metered dose inhaler. Rescue salbutamol inhalers were provided throughout the run in and study periods.

MAIN OUTCOME MEASURES

Improvement in nocturnal asthma as measured by peak expiratory flow rates and change in sleep quality as measured by electroencephalography.

RESULTS

Salmeterol improved the lowest overnight peak flow rate at both 50 micrograms (difference in median values (95% confidence interval for difference in medians) 69 (18 to 88) l/min) and 100 micrograms (72 (23 to 61) l/min) doses twice daily. While taking salmeterol 50 micrograms twice daily patients had an objective improvement in sleep quality, spending less time awake or in light sleep (-9 (-4 to -44) min) and more time in stage 4 sleep (26 (6-34) min).

CONCLUSIONS

Salmeterol is an effective long acting inhaled bronchodilator for patients with nocturnal asthma and at a dose of 50 micrograms twice daily improves objective sleep quality.

Efficacy of atropine methylnitrate alone and in combination with albuterol in children with asthma

The bronchodilator effect of nebulized AMN, albuterol and their combination was evaluated in 16 steroid-dependent asthmatic children. In phase 1, maximal bronchodilation was determined by dose-response studies on separate days. Maximal bronchodilator dose of each drug was administered either alone or in combination during phase 2. In phase 1, 0.11 +/- 0.01 mg/kg of albuterol and 0.03 mg/kg of AMN produced maximum bronchodilation. In phase 2, the peak response to albuterol occurred within 30 min and to AMN, at 60 min. Maximal FEV1 achieved after AMN was 90 percent of the maximal achieved after albuterol. AMN FEV1 response was better than for placebo for 3 h; that for albuterol was better for 4 h. Combination therapy produced a peak response similar to that of albuterol but was better than albuterol by 6 h. Thus, the maximum bronchodilator effect of AMN is less than that of albuterol in asthmatic children, but the combination may extend the period of bronchodilatation.

Airways responses to ipratropium bromide do not vary with time in asthmatic subjects. Studies of interindividual and intraindividual variation of bronchodilatation and protection against histamine-induced bronchoconstriction

Bronchial histamine provocation tests were performed in nine patients with nonallergic asthma on four consecutive days 45 minutes after inhalation of placebo or ipratropium bromide in a dose-response manner (40 micrograms, 200 micrograms, and 800 micrograms). The drugs were administered double-blind, one dose on each day. This procedure was repeated identically after three to nine months to investigate whether the bronchial responses to ipratropium bromide are constant or change with time. Ipratropium bromide induced a significantly better bronchodilation and protection against histamine-induced bronchoconstriction than placebo with no differences between the three doses. No correlation between bronchodilatation and protection was found. In six asthmatic patients ("responders") ipratropium bromide induced a significant protective effect against histamine-induced bronchoconstriction but no dose-response relationship was found. In three patients none or a very poor protective effect was found at all dose levels ("nonresponders"). The protective effect of ipratropium bromide against histamine-induced bronchoconstriction did not differ between the first and second occasion. Thus, the bronchoprotection differed between different asthmatic subjects but did not vary with time (three to nine months) within the same subject. This finding seems to be of clinical importance since it implicates that the effect of anticholinergic agents on the airways is predictable.

Oxitropium bromide: an acute dose response study of a new anticholinergic drug in combination with fenoterol in asthma and chronic bronchitis

The aim of this study was to compare the bronchodilator response of patients with either stable asthma or stable chronic bronchitis to the acute administration of oxitropium bromide and a beta agonist (fenoterol) when given both separately and together in order to determine the responses of these two groups of patients and the optimal doses of these agents when given in combination. The responses of 23 patients with asthma and 25 patients with chronic bronchitis to 400 micrograms of fenoterol, and 200 micrograms of oxitropium given either alone or together with 100, 200 or 400 micrograms of fenoterol was studied. The peak bronchodilator response to oxitropium bromide of the patients with chronic bronchitis was equivalent to the fenoterol response while, in the patients with asthma, the response to oxitropium bromide was approximately 30% of the response to fenoterol. In both groups of subjects the addition of oxitropium bromide to fenoterol significantly increased both the magnitude and the duration of the bronchodilator response without a significant increase in side effects. In both groups of subjects 200 micrograms of oxitropium bromide and 200 micrograms or more of fenoterol gave the optimal response.

Posture and nocturnal asthma

To investigate whether the supine posture caused sustained bronchoconstriction and could thus contribute to the development of nocturnal asthma, nine patients with nocturnal asthma were studied on two consecutive days, lying supine for four hours on one day and sitting upright for four hours on the other, the order of the two postures being randomised. Peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), and forced vital capacity (FVC) were measured immediately before and after the four hours and over the subsequent hour. There was no significant difference between the erect and supine posture for PEF (248 v 248 l/min), FEV1 (1.31 v 1.22 l), or FVC (2.34 v 2.28 l) at the end of the four hours, nor did any significant change develop subsequently. Thus the supine posture is not associated with prolonged bronchoconstriction. As each patient had previously shown an average overnight fall in PEF of more than 20%, this study strongly suggests that the supine posture is not an important cause of overnight bronchoconstriction.

Is nocturnal asthma caused by changes in airway cholinergic activity?

A randomised, double blind, placebo controlled crossover trial of high dose nebulised ipratropium was carried out in 10 asthmatic patients with documented nocturnal bronchoconstriction. Patients received nebulised saline or ipratropium 1 mg at 10 pm and 2 am on two nights. Absolute peak flow (PEF) rates were higher throughout the night after the patients had received ipratropium (at 2 am, for example, mean (SEM) PEF was 353 after ipratropium and 285 l/min after placebo). The fall in PEF overnight, however, was similar with ipratropium and placebo. Patients were given a further 1 mg nebulised ipratropium at 6 am on both nights. There was a significant overnight fall in PEF on the ipratropium night even when comparisons were made between the times that maximal cholinergic blockade would be expected, PEF falling between 11.30 pm and 7.30 am from 429 to 369 l/min. The percentage increase in PEF, though not the absolute values, was greater after ipratropium at 6 am than at 10 pm. These results confirm that ipratropium raises PEF throughout the night in asthmatic patients, but suggest that nocturnal bronchoconstriction is not due solely to an increase in airway cholinergic activity at night.

Comparison of the effect of oxitropium bromide and of slow-release theophylline on nocturnal asthma

The effects of a new inhaled antimuscarinic drug, oxitropium bromide, and of a slow-release theophylline preparation upon nocturnal asthma were compared in a placebo-controlled double-blind study. Two samples were studied: 12 patients received oxitropium at 600 micrograms (6 subjects) or at 400 micrograms t.i.d. (6 subjects) whereas 11 received theophylline at 300 mg b.i.d. Morning dipping, assessed by the fall in peak flow overnight, was significantly reduced in the periods when either active drug was taken, whereas no difference was noticed during the placebo administration. No significant difference was noticed between results obtained with either active drug, as well as with either dosage of oxitropium. No subject reported side effects of oxitropium, as compared to three subjects reporting nausea, vomiting and tremors after theophylline. Oxitropium proves to be a valuable alternative to theophylline in nocturnal asthma, since it is equally potent, safer and does not require the titration of dosage.

Validation of morning dip of peak expiratory flow as an indicator of the severity of nocturnal asthma

Overnight falls in peak expiratory flow (PEF) (with the morning dip of the index) may be considered the hallmark of nocturnal asthma. To validate the morning dip a quantitative marker of the degree of nocturnal bronchoconstriction, the dip was measured in 11 subjects (six with a history consistent with nocturnal asthma) undergoing all-night monitoring of lower respiratory resistance by a double-catheter method. In six subjects, marked and recurrent increases in resistance were recorded, along with morning dips higher than 20 percent; however, on the following morning, only two of them reported having suffered significant breathlessness and wheeze. Peak and average values for resistance, as well as the duration for which resistance was increased, were closely correlated with the magnitude of morning dips. Therefore, unlike the subjective report, PEF may be considered a reliable quantitative indicator of nocturnal bronchoconstriction.