Inhaled therapy reduces morning dips in asthma

Effect of high dose inhaled glucocorticoids on quality of life in patients with moderate to severe asthma

Asthma is a chronic disorder that can place considerable restrictions on the physical, emotional, and social aspects of the lives of patients. Inhaled glucocorticoids (GCs) are the most effective controller therapy. The purpose of this study was to evaluate the effect of inhaled GCs on quality of life in patients with moderate to severe asthma. Patients completed the asthma quality of life questionnaire (AQLQ) and pulmonary function test at baseline and after 4 wks treatment of GCs. We enrolled 60 patients who had reversibility in FEV1 after 200 microgram of albuterol of 15% or more and/or positive methacholine provocation test, and initial FEV1% predicted less than 80%. All patients received inhaled GCs (fluticasone propionate 1,000 microgram/day) for 4 wks. The score of AQLQ was significantly improved following inhaled GCs (overall 51.9+/-14.3 vs. 67.5+/-12.1, p<0.05). The change from day 1 to day 28 in FEV1 following inhaled GCs was diversely ranged from -21.0% to 126.8%. The improvement of score of AQLQ was not different between at baseline and after treatment of GCs according to asthma severity and GCs responsiveness. Quality of life was improved after inhaled GCs regardless of asthma severity and GCs responsiveness in patients with moderate to severe asthma.

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.

Improving asthma control through telemedicine: a study of short-message service

Home peak expiratory flow (PEF) measurement is recommended by asthma guidelines. In a 16-week randomized controlled study on 16 subjects with asthma (24.6 6.5 years old, asthma duration small ze, Cyrillic 6 months), we examined Global System for Mobile Communications (GSM) mobile telephone short-message service (SMS) as a novel means of telemedicine in PEF monitoring. All subjects received asthma education, self-management plan, and standard treatment. All measured PEF three times daily and kept a symptom diary. In the study group, therapy was adjusted weekly by an asthma specialist according to PEF values received daily from the patients. There was no significant difference between the groups in absolute PEF, but PEF variability was significantly smaller in the study group (16.12 +/- 6.93% vs. 27.24 +/- 10.01%, p = 0.049). forced expiratory flow in 1 second (FEV1; % predicted) in the study group was slightly but significantly increased (81.25 +/- 17.31 vs. 77.63 +/- 14.80, p = 0.014) and in the control group, unchanged (78.25 +/- 21.09 vs. 78.88 +/- 22.02, p = 0.497). Mean FEV1 was similar in the two groups both before and after the study. Controls had significantly higher scores for cough (1.85 +/- 0.43 vs. 1.42 +/- 0.28, p < 0.05) and night symptoms (1.22 +/- 0.23 vs. 0.85 +/- 0.32, p < 0.05). There was no significant difference between the groups in daily consumption of inhaled medicine, forced vital capacity, or compliance. Per patient, per week, the additional cost of follow-up by SMS was Euros 1.67 (equivalent to approximately $1.30 per 1 Euro), and SMS transmission required 11.5 minutes. Although a study group of 40 patients is needed for the follow-up study to achieve the power of 80% within the 95% confidence interval, we conclude that SMS is a convenient, reliable, affordable, and secure means of telemedicine that may improve asthma control when added to a written action plan and standard follow-up.

An Internet survey of asthma treatment

The aim of this investigation was to study pharmacological treatment in relation to asthma severity among patients visiting an asthma web site on the Internet. The study comprised 650 subjects from 30 countries with self-reported asthma that participated in an Internet based patient survey. The survey was posted on the web site Asthma Information Centre (www.mdnet.de). Moderate or severe night cough or wheezing was reported by 43% and activity limitation by 55% of the asthmatics. Short-acting beta-agonists were used by 67% and inhaled steroids by 59%. The use of short-acting beta-agonists decreased with age, whereas the use of inhaled steroids, long-acting beta-agonists and antileukotrienes was lowest in the youngest (0-20 years) and highest age groups (> 60 years). The use of short-acting beta-agonists increased, and the use of inhaled steroids decreased with the severity of nocturnal symptoms (p < 0.01). Side effects were most often reported for oral beta-agonists (42%) and least often for antileukotrienes (9%). We conclude that despite problems with selection and external validity, an online asthma survey produces results that agree highly with more resource-demanding surveys. We find that many asthmatics have a low level of asthma control, and the survey indicates that underuse of inhaled steroids is one of the reasons why the goals set up in asthma guidelines so far have not been reached.

Nocturnal asthma uncontrolled by inhaled corticosteroids: theophylline or long-acting beta2 agonists?

Asthma is an inflammatory disease of the airways that is frequently characterised by marked circadian rhythm. Nocturnal and early morning symptoms are quite common among patients with asthma. Increased mortality and decreased quality of life are associated with nocturnal asthma. Although numerous mechanisms contribute to the pathophysiology of nocturnal asthma, increasing evidence suggests the most important mechanisms relate to airway inflammation. According to international guidelines, patients with persistent asthma should receive long term daily anti-inflammatory therapy. A therapeutic trial with anti-inflammatory therapy alone (without a long-acting bronchodilator) should be assessed to determine if this therapy will eliminate nocturnal and early morning symptoms. If environmental control and low to moderate doses of inhaled corticosteroids do not eliminate nocturnal symptoms, the addition of a long-acting bronchodilator is warranted. Long-acting inhaled beta2 agonists (e.g. salmeterol, formoterol) are effective in managing nocturnal asthma that is inadequately controlled by anti-inflammatory agents. In addition, sustained release theophylline and controlled release oral beta2 agonists are effective. In patients with nocturnal symptoms despite low to high doses of inhaled corticosteroids, the addition of salmeterol has been demonstrated to be superior to doubling the inhaled corticosteroid dose. In trials comparing salmeterol with theophylline, 3 studies revealed salmeterol was superior to theophylline (as measured by e.g. morning peak expiratory flow, percent decrease in awakenings, and need for rescue salbutamol), whereas 2 studies found the therapies of equal efficacy. Studies comparing salmeterol to oral long-acting beta2 agonists reveal salmeterol to be superior to terbutaline and equivalent in efficacy to other oral agents. Microarousals unrelated to asthma are consistently increased when theophylline is compared to salmeterol in laboratory sleep studies. In addition to efficacy data, clinicians must weigh benefits and risks in choosing therapy for nocturnal asthma. Long-acting inhaled beta2 agonists are generally well tolerated. If theophylline therapy is to be used safely, clinicians must be quite familiar with numerous factors that alter clearance of this drug, and they must be prepared to use appropriate doses and monitor serum concentrations. Comparative studies using validated, disease specific quality of life instruments (e.g. Asthma Quality of Life Questionnaire) have shown long-acting inhaled beta2 agonists are preferred to other long-acting bronchodilators. Examination of costs for these therapeutic options reveals that evening only doses of long-acting oral bronchodilators are less expensive than multiple inhaled doses. However, costs of monitoring serum concentrations, risks, quality of life and otheroutcome measures must also be considered. Long-acting inhaled beta2 agonists are the agents of choice for managing nocturnal asthma in patients who are symptomatic despite anti-inflammatory agents and other standard management (e.g. environmental control). These agents offer a high degree of efficacy along with a good margin of safety and improved quality of life.

Addition of inhaled salmeterol to inhaled corticosteroids in patients with poorly controlled nocturnal asthma

The effect of adding inhaled salmeterol to inhaled corticosteroids was studied in patients with poorly controlled nocturnal asthma. In a double-blind, cross-over study, 20 patients were randomized to receive either salmeterol 50 micrograms twice daily or placebo via a Diskhaler after a 1-week run-in period. After 4 weeks of treatment, patients were subsequently crossed over to receive the other treatment for a further 4 weeks with a 2-week wash-out period in between. The response to treatment was assessed by peak expiratory flow rates (PEF) measured in the morning and evening, symptom scores of asthma, number of bronchodilators used, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) at regular intervals. Patients' preference for the Diskhaler or metered-dose inhaler was assessed at the last visit. The results showed that morning PEF was significantly higher while on salmeterol than on placebo (296.9 +/- 70.2 vs 274.6 +/- 77.4 L/min). Evening PEF showed a trend towards a higher value while on salmeterol than on placebo (321.1 +/- 73.4 vs 288.7 +/- 79.4 L/min), but the difference was not significant. There was no statistically significant improvement in symptom scores, number of rescue bronchodilators used and FEV1 or FVC between the two treatment groups. The occurrence of side effects in terms of tremors and palpitations between treatment and placebo were similar. There were more patients who preferred Diskhaler to metered-dose inhaler (70% vs 30%). We conclude that salmeterol 50 micrograms twice daily produces significant improvement in morning PEF and is well tolerated in patients with nocturnal asthma. Diskhaler is a device which is easy to use and preferred to a metered-dose inhaler.

The beta-agonist controversy

After many years of increasing morbidity and mortality, several avenues of scientific investigation now appear to be converging to offer an explanation for the asthma paradox and indicate that regular or long-term use of short-acting inhaled beta-agonist drugs is inappropriate. Pharmacoepidemiologic studies indicate a strong association between increased beta-agonist use and asthma deaths, which does not appear entirely related to confounding by severity. Clinical data, although still limited, show little evidence for symptomatic or functional improvement during long-term beta-agonist therapy and, in many instances, reveal significant adverse effects. Related investigations offer evidence of potential plausible mechanisms, notably increased bronchial responsiveness to inhaled allergen, to explain these findings. A radical revision of the therapeutic use of these drugs in asthma has been prompted by these findings. Beta-agonist drugs remain essential for the management of acute severe attacks. They are also useful on demand for the relief of breakthrough symptoms and for prophylaxis of exercise-induced symptoms. In chronic asthma, however, adequate anti-inflammatory therapy is the treatment of choice. Long-term treatment with short-acting beta-agonist, even in the presence of seemingly adequate anti-inflammatory therapy, may be associated with deterioration of asthma over the long-term. The effects of long-acting beta-agonists remain under review. To date, there are no data that clearly indicate a deleterious effect, and many clinical trials show benefits in symptom control and improved lung function associated with their regular use. The significance of tachyphylaxis remains to be defined. Their current role is still somewhat unclear, but they have been successfully used in subjects in whom, despite the use of moderate doses of inhaled corticosteroid, short-acting bronchodilator is still frequently required. The use of twice-daily long-acting beta-agonist appears preferable to frequent use of short-acting beta-agonists.

Treatment of nocturnal asthma by addition of oral slow-release albuterol to standard treatment in stable asthma patients

Nocturnal and early-morning complaints in asthma patients are sometimes difficult to treat. We investigated the efficacy of an oral osmotically controlled release (OR) formulation of albuterol 8 mg in 35 patients with stable asthma and nocturnal complaints and/or morning dipping of the peak expiratory flow (PEF). The mean age was 45 years (range 22-70), the FEV(1) was 61 +/- 20% of predicted, and inhaled steroids were used by 32 patients. Albuterol OR was added to their usual treatment. The use of theophyllines and oral adrenergics was not allowed. Twice-daily (b.i.d.) dosing was compared to one dose at night and to placebo. The three-period crossover study was double-blind placebo-controlled with treatment periods of 2 weeks. Responses have been analyzed by means of multiple regression analysis at a significance level of 5%. There was no significant difference of the FEV(1) or the weekly means of PEFs between the periods. During the b.i.d. treatment, the daytime and nocturnal symptom scores, used rescue medication, subjective sleep quality, and nocturnal waking tended to be better. Mental fitness was improved, but significantly only in the morning. We concluded that additional treatment with albuterol 8 mg OR once or twice daily did not lead to an overall clinical improvement in this group of patients with nocturnal asthma during standard treatment. In view of the tendency to improvement, it may be worth trying this treatment in individual patients.

A double-blind comparison of inhaled budesonide, long-acting theophylline, and their combination in treatment of nocturnal asthma

In 61 patients with nocturnal asthma, the effects of budesonide, an inhaled steroid (Pulmicort; 200 micrograms twice daily), long-acting theophylline (Theodur; 200 mg twice daily), and their combination were compared. After a 2-week placebo run-in period, the patients were entered into double-blind, crossover periods of 3 weeks. Patients were allowed to use inhaled beta 2-agonists as required throughout the study. Morning and evening peak expiratory flow rate (PEFR) (percentage of predicted normal +/- SEM) was significantly higher during the budesonide (morning 77 +/- 1%; evening 80 +/- 1%) and combination therapy (morning 79 +/- 1%; evening 81 +/- 1%) than the theophylline treatment (morning 74 +/- 1%; evening 76 +/- 1%; P < 0.01, respectively). Significantly fewer sleep disturbances and fewer nighttime inhalations of beta 2-agonists were required during budesonide and combination therapy than theophylline treatment. No statistically significant differences were seen between combined therapy and budesonide alone. Budesonide, an inhaled steroid, was significantly better than the bronchodilator, theophylline, in controlling nocturnal asthma, but no additional improvement in efficacy was seen when the drugs were used in combination.

An epidemiological investigation into nocturnal asthma

The prevalence of nocturnal asthma and its relationship with clinical features of the disease were studied in 150 consecutive patients. Nearly three-fourths of patients had nocturnal symptoms of asthma, either currently or in the past. There was no relation between the tendency to develop nocturnal symptoms and age, sex, atopic status, or periodicity of the disease. However, those with more severe asthma had a greater tendency to develop nocturnal symptoms. Patients currently having nocturnal symptoms had a poorer lung function.

The beta 2-agonist controversy. Observations, explanations and relationship to asthma epidemiology

Links between frequent use of inhaled beta 2-agonists and morbidity and mortality from asthma appear probable. Two mortality epidemics followed the marketing of potent inhaled adrenergic agents. Case-control studies in New Zealand linked mortality with prescription of fenoterol, especially in severe asthma. A Saskatchewan case-control study confirmed an association of mortality with fenoterol, and also with frequent use of salbutamol (albuterol). Cardiac effects of beta 2-agonists do not cause mortality, but frequent use of these agents may increase the chronic severity of asthma, hence increasing the number of asthmatic patients at risk of death in an acute attack. Frequent use of beta 2-agonists may reduce lung function, increasing airway responsiveness, and impair control of asthma, despite use of inhaled corticosteroids. Mechanisms for this effect may include tachyphylaxis to nonbronchodilator effects, increased responsiveness to allergen, interaction with corticosteroid receptors, altered mucociliary function, differential effects of enantiomers, and masking of symptoms by beta 2-agonist use. The withdrawal of fenoterol from New Zealand in 1990 was associated with a substantial decline in morbidity and mortality. Overall, the evidence suggests that frequent use of inhaled beta 2-agonists has a deleterious effect on the control of asthma. Epidemics of mortality are explained by an increase in chronic severity of asthma following introduction of more potent beta 2-agonists. While beta 2-agonists remain essential for relief of breakthrough symptoms, long term use, particularly with high doses of potent agents, appears to be detrimental.

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.

Budesonide and terbutaline or terbutaline alone in children with mild asthma: effects on bronchial hyperresponsiveness and diurnal variation in peak flow

The effects of treatment with budesonide (200 micrograms twice daily) and terbutaline (500 micrograms four times daily) has been compared with the effects of placebo and terbutaline in 27 children with mild asthma, aged 7-14 years, in a double blind, randomised placebo controlled study over eight weeks. Bronchial responsiveness (PC20 histamine), lung function, the amplitude of diurnal variation in peak expiratory flow (PEF), and symptom scores were measured. Baseline FEV1 was over 70% predicted and PC20 histamine less than 8 mg/ml. Twelve children were treated with budesonide and terbutaline and 15 with placebo and terbutaline. After four and eight weeks of treatment the change in PC20 was significantly greater after budesonide and terbutaline than after terbutaline alone by 2.1 (95% CI 0.5-3.8) and 1.3 (95% CI 0.1-2.5) doubling doses respectively. Mean FEV1 did not change in either group. The change in afternoon and nocturnal PEF was significantly greater after budesonide and terbutaline than after terbutaline alone. The amplitude of diurnal variation in PEF did not change significantly in either group. Peak flow reversibility decreased in the budesonide group. There were no differences between treatments for cough and dyspnoea, but wheeze improved in the budesonide group. The children with mild asthma treated with budesonide and terbutaline showed improvement in bronchial responsiveness, afternoon and nocturnal PEF, and symptoms of wheeze and a fall in peak flow reversibility by comparison with those who received terbutaline alone.

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.

Long-term management of reversible obstructive airways disease in adults

The goals of the long-term management of reversible obstructive airways disease (ROAD) are to find the minimum treatment that controls symptoms, allows resumption of normal life, prevents severe attack and death, and controls airflow obstruction. ROADs include asthma, chronic bronchitis, and emphysema. Although the differential diagnosis between these different entities may be difficult, they share the same possibilities of pharmacotherapy, including bronchodilator and antiinflammatory drugs. beta 2-agonists administered via inhaled route produce the best bronchodilator/side effects ratio, provided that the drugs reach the bronchi. This underlines the importance of a proper inhalation technique when using a metered-dose inhaler. In patients with hand-breath coordination problems, powder inhalers or spacer devices are useful to ameliorate the therapeutic efficacy of inhaled drugs. Anticholinergic agents are usually less potent bronchodilators than inhaled beta 2 agonists in asthma, but they may have additive effects when associated with beta 2 agonists. Only a therapeutic trial with peak-flow monitoring can demonstrate the efficacy of anticholinergic drugs in individuals. Theophylline's kinetics are characterized by a narrow therapeutic index with high inter- and intraindividual variabilities. Sodium cromoglycate and nedocromil sodium are antiallergic drugs, the efficacy of which has been demonstrated in controlled studies. Corticosteroids are the most efficient anti-asthma drugs. Inhaled corticosteroid dosing should be tailored to each individual. If inhaled corticosteroid therapy is used in an oral corticosparing attempt, patients should be followed-up during several months. The management of ROAD includes the diagnostic procedures, the identification of triggers and inducers of airways obstruction, the assessment of severity of the disease, and then the treatment and education of the patient. Strategy design to achieve proper use of drugs by patients is discussed.

Nocturnal asthma: effect of treatment with oral sustained-release terbutaline, inhaled budesonide, and the two in combination

The purpose of this study was to compare effect of treatment with an oral long-acting beta 2-agonist (sustained-release terbutaline, Bricanyl depot), an inhaled steroid (budesonide, Pulmicort), and the combined treatment in patients with nocturnal asthma. Thirty-seven patients completed the study. During a 1-week run-in period with inhaled terbutaline monotherapy, the mean nocturnal asthma score was 1.0 (+/- 0.1) (corresponding to one awakening every night), and the mean overnight fall in peak expiratory flow rate was 27.7% (+/- 2.0). The patients were randomly entered into double-blind, crossover periods of 3 weeks each: (1) sustained-release terbutaline, 10 mg twice daily (b.i.d.), (2) sustained-release terbutaline, 10 mg b.i.d., and two puffs (400 micrograms) of budesonide, b.i.d., and (3) two puffs (400 micrograms) of budesonide, b.i.d. The combined treatment resulted in significantly lower overnight fall in peak expiratory flow rate (6.9% +/- 1.4 compared to 9.4% +/- 2.0 during sustained-release terbutaline and 10.4% +/- 1.9 during budesonide) and less nocturnal awakenings (nocturnal asthma score 0.15 +/- 0.05, 0.43 +/- 0.09, and 0.26 +/- 0.06, respectively) than either single treatment alone (p less than 0.05). The differences between the single treatments were not significant. We thus found that an inhaled steroid is as effective as a long-acting oral beta 2-agonist in controlling nocturnal asthma and that the combination is better. The observed differences were, however, small, and other studies would be required to evaluate the clinical significance of the present finding.

Controlled release salbutamol tablets versus sustained release theophylline tablets in the control of reversible obstructive airways disease

A crossover pilot study was undertaken to compare the acceptability of controlled release salbutamol tablets (8 mg twice daily) with a sustained release theophylline preparation (400-800 mg given once each night) in patients with reversible obstructive airways disease. A 2-week run-in period was used to titrate the theophylline dosage. Patients were then allocated at random to one of the treatments before being immediately crossed over to the other for a further 4 weeks. Thirty-two patients, aged 17-66 years, entered the trial. Seventeen patients (53%) were withdrawn. The majority of the 13 withdrawals due to side-effects of theophylline occurred during the run-in period. There were no statistically significant differences between treatments for either lung function tests performed at the clinic or for peak expiratory flow rate recorded by the patients. The non-asthma symptom score was significantly higher with theophylline than with the salbutamol preparation. A preference for treatment with the controlled release salbutamol tablets was expressed by 11/15 patients.

Nocturnal cough in asthma

The timing of nocturnal cough and its association with change in ambient temperature was documented in 11 asthmatic children, median age 5.1 years, while they were receiving continuous prophylaxis. Studies were performed in their homes on three nights. A voice activated system with electronic time signal recorded coughing. Ambient temperature was recorded every five minutes throughout the night on a Grant Squirrel data logger. Ten children coughed on 27 nights with a median of six bouts of coughing a night (range 0-272). The cough rate in the two hours after going to bed was significantly higher than the cough rate in the middle of the night (2-4 am or 4-6 am). Peak coughing times were 7-9 pm and 6-8 am. The room temperature was lowest between 5 and 7 am. There were no significant differences between cough rates during periods of rapid temperature change (more than 1 degree C an hour). The timing of nocturnal cough observed in this study differed from the known basophase of circadian cycles described for adults and children.

Is there a circadian variation in respiratory morbidity?

In a retrospective study of the time of presentation to an accident and emergency department patients with acute respiratory symptoms presented more commonly at night compared to a control group with abdominal pain. In a subsequent prospective study doctors from a GP deputizing service were called much more frequently at night by patients with asthma than by those with other symptoms. These findings refute the suggestion that the observed increased mortality from respiratory diseases at night results from reduced medical care as a consequence of a reluctance of patients to present during the night.

Diurnal rhythm of asthma

A diurnal rhythm in the occurrence and severity of asthma symptoms is almost universal with disturbed sleep due to enhanced symptoms at night paralleled by a change in lung function. The mechanisms involved are not completely understood. However, it appears to be related to an exaggerated response to a circadian rhythm in lung function observed in healthy individuals. The circadian nature of asthma must be considered in diagnosis and evaluating the adequacy of therapy. Inhaled therapy with additional suppressive and anti-inflammatory treatment as required should be effective in treating most patients with nocturnal asthma.

Reduction of nocturnal asthma by an inhaled anticholinergic drug

Although the mechanisms of nocturnal asthma are still uncertain, increased vagal cholinergic tone may be contributory factor. To examine this hypothesis, we have studied the effect of an anticholinergic drug, oxitropium bromide, on the early morning fall in peak expiratory flow (PEF) in patients with nocturnal asthma. Eighteen patients (aged 18 to 76 years; seven men) with documented nocturnal asthma were studied in a double-blind randomized cross-over study in which they received either oxitropium bromide (200 micrograms or 400 micrograms) or placebo in a single dose at night for two-week periods. With placebo the mean (+/- SE) fall in PEF (expressed as percentage of evening PEF) was 17.3 +/- 2.0 percent, which was significantly reduced to 10.3 +/- 3.3 percent after oxitropium (400 micrograms) (p less than 0.05; ANOVA). Closer analysis revealed that nine of the 18 patients had responded in a dose-dependent manner, with the mean percentage decreases with placebo, 200 micrograms, and 400 micrograms of oxitropium being 19.1 +/- 3.2, 11.5 +/- 4.4, and 5.0 +/- 4.5 percent, respectively (p less than 0.01 between each treatment). The remaining patients were unaffected by therapy. There were no differences between "responders" and "non-responders" in terms of age, atopic status, duration of asthma, severity of asthma, or bronchodilator response to albuterol (salbutamol). There were no differences in nocturnal symptoms between periods of treatment, and no side effects were recorded. We conclude that anticholinergic drugs may protect against nocturnal asthma in some patients, indicating the involvement of vagal cholinergic mechanisms.

Breathing during sleep in stable asthmatic subjects. Influence of inhaled bronchodilators

The bronchoconstriction of asthma displays a circadian rhythm with exacerbations often occurring in the early morning hours. Gas exchange abnormalities during sleep in patients with severe asthma have been documented; however, the influence of sleep on gas exchange in the asthmatic with few or no daytime or nocturnal symptoms is poorly understood. To determine if abnormalities in oxygenation might occur during sleep, we studied 12 stable adult asthmatic patients with reversible airflow obstruction during sleep on three consecutive nights, with night 1 being for acclimatization. On test nights 2 and 3, the subjects received, in random double-blind fashion, either inhaled fenoterol or its placebo. Spirometry was performed before and after bronchodilator treatment and on the next morning. The mean FEV1 was 63 percent predicted before treatment. There was significant (p less than 0.05) improvement in FEV1 on fenoterol night after treatment which was also present the next morning. Mean prefenoterol FEV1 was 2.04 +/- .15 (SEM) and increased to 2.61 +/- .17 after the bronchodilator. The mean morning FEV1 was 2.27 +/- .20. Mean preplacebo FEV1 was 2.07 +/- .12 and did not change significantly with placebo bronchodilator. Sleep analysis demonstrated no significant differences in total sleep time or duration of oxyhemoglobin desaturation between nights. The incidence of sleep disordered breathing was very low (0.14 apneas/hour). The frequency of apneas and hypopneas did not change significantly with treatment. Two of the 12 subjects experienced an asthma attack on placebo night which did not recur following active bronchodilator administration. We conclude that stable asthmatic patients with few nocturnal complaints have a low frequency of disordered breathing and desaturation events during sleep.

Nocturnal asthma and timing of treatment

Nocturnal deterioration of pulmonary function in asthmatic patients is a well-recognized and well-documented phenomenon. The mechanism of this "morning dip," however, remains uncertain. Although the circadian rhythms of body temperature, corticosteroid, catecholamine, histamine, and opiate peptide levels, and even sleep itself have been shown to be in phase with the diurnal variation in asthma, a causal relationship has yet to be established. Increased nighttime bronchial reactivity to histamine, acetylcholine, and house dust allergen have been demonstrated. In general, continuous treatment with theophylline, beta-adrenergic agonists, or corticosteroids attenuates the degree of morning dip but does not completely eliminate the circadian rhythm of asthma. The significance of nocturnal asthma is emphasized by the observation that asthma deaths occur more frequently during nighttime hours and are often preceded by large daily swings in peak expiratory flow. Further studies examining the etiology and treatment of nocturnal asthma are needed.