Twelve month comparison of salmeterol and salbutamol as dry powder formulations in asthmatic patients. European Study Group

Long-acting inhaled medicines: Present and future

Inhaled medicines continue to be an essential part of treatment for respiratory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. In addition, inhalation technology, which is an active area of research and innovation to deliver medications via the lung to the bloodstream, offers potential advantages such as rapid onset of action, enhanced bioavailability, and reduced side effects for local treatments. Certain inhaled macromolecules and particles can also end up in different organs via lymphatic transport from the respiratory epithelium. While the majority of research on inhaled medicines is focused on the delivery technology, particle engineering, combination therapies, innovations in inhaler devices, and digital health technologies, researchers are also exploring new pharmaceutical technologies and strategies to prolong the duration of action of inhaled drugs. This is because, in contrast to most inhaled medicines that exert a rapid onset and short duration of action, long-acting inhaled medicines (LAIM) improve not only the patient compliance by reducing the dosing frequency, but also the effectiveness and convenience of inhaled therapies to better manage patients' conditions. This paper reviews the advances in LAIM, the pharmaceutical technologies and strategies for developing LAIM, and emerging new inhaled modalities that possess a long-acting nature and potential in the treatment and prevention of various diseases. The challenges in the development of the future LAIM are also discussed where active research and innovations are taking place.

Salbutamol in the Management of Asthma: A Review

Asthma is a common inflammatory disease of the lungs. The prevalence of asthma is increasing worldwide, and the tendency indicates that the number of asthma sufferers will soar in the coming years for several reasons, in particular, the lifestyles we have adopted that expose us to risk factors. Salbutamol is the first selective short-acting β2-agonist (SABA) used as an alternative reliever in the treatment of asthma. Its therapeutic effect is based on its potent smooth muscle relaxant properties, which allow the inhibition of bronchial smooth muscle contraction and subsequent bronchodilation. Salbutamol can be administered orally, intravenously (IV), intramuscularly (IM), subcutaneously, or by inhalation. For this reason, the pharmacokinetic (PK) parameters-absorption, distribution, metabolism, and elimination-are highly diverse and, consequently, the efficacy and adverse effects also differ between each formulation. Here, we review the pharmacological profile of different salbutamol formulations, focusing on their efficacy and adverse effects for its original application, asthma.

Potential adverse effects of bronchodilators in the treatment of airways obstruction in older people: recommendations for prescribing

Asthma and chronic obstructive pulmonary disease (COPD) are common disorders that are associated with increasing morbidity and mortality in older people. Bronchodilators are used widely in patients with these conditions, but even when used in inhaled form can have systemic as well as local effects. Older people experience more adverse drug effects because of pharmacodynamic and pharmacokinetic changes and particularly drug-drug and drug-disease interactions. Cardiovascular disease is common in older people and beta-adrenoceptor agonists (beta-agonists) have inotropic and chronotropic effects that can increase arrhythmias and cardiomyopathy. They can also worsen or induce myocardial ischaemia and cause electrolyte disturbances that contribute to arrhythmias. Tremor is a well known distressing adverse effect of beta-agonist administration. Long-term beta-agonist use can be associated with tolerance, poor disease control, sudden life-threatening exacerbations and asthma-related deaths. Functional beta2-adrenoceptors are present in osteoblasts, and chronic use of beta-agonists has been implicated in osteoporosis. Inhaled anticholinergics are usually well tolerated but may cause dry mouth, which can be troublesome in older people. Pupillary dilatation, blurred vision and acute glaucoma can occur from escape of droplets from loosely fitting nebulizer masks. Although ECG changes have not been seen in randomized controlled trials of long-acting inhaled anticholinergics, supraventricular tachycardias have been observed in a 5-year randomized controlled trial of ipratropium bromide. Paradoxical bronchoconstriction can occur with inhaled anticholinergics as well as with beta-agonists, but tolerance has not been reported with anticholinergics. Anticholinergic drugs also cause central effects, most notably impairment of cognitive function, and these effects have been noted with inhaled agents. Use of theophylline is limited by its adverse effects, which range from commonly occurring gastrointestinal symptoms to palpitations, arrhythmias and reports of myocardial infarction. Seizures have been reported, but are rare. Theophylline is metabolized primarily by the liver, and commonly interacts with other medications. Its concentration in plasma should be monitored closely, especially in older people. Although many clinical trials have been conducted on bronchodilators in obstructive airways disease, the results of these clinical trials need to be interpreted with caution as older people are often under-represented and subjects with co-morbidities actively excluded from these trials.

Regular treatment with salmeterol for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular salmeterol versus placebo or regular short-acting beta(2)-agonists.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and FDA submissions in relation to salmeterol were also checked. The date of the most recent search was October 2007.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular salmeterol and were of at least 12 weeks duration. Concomitant use of inhaled corticosteroids was allowed, as long as this was not part of the randomised treatment regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data was extracted by one author and checked by the second author. Unpublished data on mortality and serious adverse events was sought.

MAIN RESULTS

The review includes 26 trials comparing salmeterol to placebo and 8 trials comparing with salbutamol. These included 62,630 participants with asthma (including 2,380 children). In 6 trials (2,766 patients), no serious adverse event data could be obtained. All cause mortality was higher with regular salmeterol than placebo but the increase was not significant, Odds Ratio 1.33 [95% CI: 0.85, 2.10]. Non-fatal serious adverse events were significantly increased when regular salmeterol was compared with placebo, Odds Ratio 1.14 [95% CI: 1.01, 1.28]. One extra serious adverse event occurred over 28 weeks for every 188 people treated with regular salmeterol [95% CI: 95 to 2606]. There is insufficient evidence to assess whether the risk in children is higher or lower than in adults. No significant increase in fatal or non-fatal serious adverse events was found when regular salmeterol was compared with regular salbutamol. Individual patient data from the SNS study have been combined with the results of the SMART study; in patients who were not taking inhaled corticosteroids, compared to regular salbutamol or placebo, there was a significant increase in risk of asthma-related death with regular salmeterol, Odds Ratio 9.52 [95% CI: 1.24, 73.09]. The confidence interval for patients taking inhaled corticosteroids is too wide to rule out an increase in asthma mortality in this group.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular salmeterol. There is also a clear increase in risk of asthma-related mortality in patients not using inhaled corticosteroids in the two large surveillance studies. Although the increase in asthma-related mortality was smaller in patients taking inhaled corticosteroids at baseline, the confidence interval is wide, so it cannot be concluded that the inhaled corticosteroids abolish the risks of regular salmeterol. The adverse effects of regular salmeterol in children remain uncertain due to the small number of children studied.

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.

Comparison of the effects of salmeterol/fluticasone propionate with fluticasone propionate on airway physiology in adults with mild persistent asthma

Background

This study compared the effect of inhaled fluticasone propionate (FP) with the combination of salmeterol/fluticasone propionate (SFC) on lung function parameters in patients with mild asthma.

Methods

Adult patients with mild persistent asthma (≥ 80% predicted FEV₁) receiving 200–500 μg of BDP or equivalent were randomised to receive either FP 100 μg or SFC 50/100 μg twice daily from a Diskus^® inhaler for four weeks. The primary outcome was the change from baseline in airway resistance (sRaw) at 12 hrs post dose measured by whole body plethysmography. Impulse oscillometry and spirometry were also performed.

Results

A comparison of the geometric mean sRaw at 12 hrs post dose in the SFC group to the FP group gave a ratio of 0.76 (0.66 – 0.89, p < 0.001) at week 2 and 0.81 (0.71 – 0.94, p = 0.006) at week 4. Similarly, significant results in favour of SFC for oscillometry measurements of resistance and reactance were observed. FEV₁ was also significantly superior at week 2 in the SFC group (mean difference 0.16L, 95% CI; 0.03 – 0.28, p = 0.015), but not at week 4 (mean difference 0.17L, 95% CI -0.01 – 0.34, p = 0.060).

Conclusion

SFC is superior to FP in reducing airway resistance in mild asthmatics with near normal FEV₁ values. This study provides evidence that changes in pulmonary function in patients with mild asthma are detected more sensitively by plethysmography compared to spirometry

Trial registration number

NCT00370591.

Long-acting beta2-agonists for chronic asthma in adults and children where background therapy contains varied or no inhaled corticosteroid

BACKGROUND

Asthma is a common respiratory disease among both adults and children and short acting inhaled beta-2 agonists are used widely for 'reliever' bronchodilator therapy. Long acting beta-2 agonists (LABA) were introduced as prospective 'symptom controllers' in addition to inhaled corticosteroid 'preventer' therapy (ICS). In this updated review we have included studies in which patients were either not on ICS as a group, or in which some patients, but not all, were on ICS to complement previous systematic reviews of studies where LABA was given in patients uniformly receiving ICS. We have focussed particularly on serious adverse events, given previous concerns about potential risks, especially of death, from regular beta-2 agonist use.

OBJECTIVES

This review aimed to determine the benefit or detriment on the primary outcome of asthma control with the regular use of LABA compared with placebo, in mixed populations in which only some were taking ICS and in populations not using ICS therapy.

SEARCH STRATEGY

We carried out searches using the Cochrane Airways Group trial register, most recently in October 2005. We searched bibliographies of identified RCTs for additional relevant RCTs and contacted authors of identified RCTs for other published and unpublished studies.

SELECTION CRITERIA

All randomised studies of at least four weeks duration, comparing a LABA given twice daily with a placebo, in chronic asthma. Selection criteria to this updated review have been altered to accommodate recently published Cochrane reviews on combination and addition of LABA to ICS therapy. Studies in which all individuals were uniformly taking ICS were excluded from this review.

DATA COLLECTION AND ANALYSIS

Two reviewers performed data extraction and study quality assessment independently. We contacted authors of studies for missing data.

MAIN RESULTS

Sixty-seven studies (representing 68 experimental comparisons) randomising 42,333 participants met the inclusion criteria. Salmeterol was used as long-acting agent in 50 studies and formoterol fumarate in 17. The treatment period was four to nine weeks in 29 studies, and 12 to 52 weeks in 38 studies. Twenty-four studies did not permit the use of ICS, and forty permitted either inhaled corticosteroid or cromones (in three studies this was unclear). In these studies between 22% and 92% were taking ICS, with a median of 62%. There were significant advantages to LABA treatment compared to placebo for a variety of measurements of airway calibre including morning peak expiratory flow (PEF), evening PEF and FEV1. They were associated with significantly fewer symptoms, less use of rescue medication and higher quality of life scores. This was true whether patients were taking LABA in combination with ICS or not. Findings from SMART (a recently published surveillance study) indicated significant increases in asthma related deaths, respiratory related deaths and combined asthma related deaths and life threatening experiences. The absolute increase in asthma-related mortality was consistent with an increase of around one per 1250 patients treated with LABA for six months, but the confidence intervals are wide (from 700 to 10,000). Post-hoc exploratory subgroups suggested that African-Americans and those not on inhaled corticosteroids were at particular risk for the primary end-point of death or life-threatening asthma event. There was also a suggestion of an increase in exacerbation rate in children. Pharmacologically predicted side effects such as headache, throat irritation, tremor and nervousness were more frequent with LABA treatment.

AUTHORS' CONCLUSIONS

LABA are effective in the control of chronic asthma in the "real-life" subject groups included. However there are potential safety issues which call into question the safety of LABA, particularly in those asthmatics who are not taking ICS, and it is not clear why African-Americans were found to have significant differences in comparison to Caucasians for combined respiratory-related death and life threatening experiences, but not for asthma-related death.

Long-acting beta2-agonists: comparative pharmacology and clinical outcomes

Salmeterol and formoterol are both long-acting beta(2)-adrenoceptor agonists (beta(2)-agonists). They both provide excellent bronchodilating and bronchoprotective effects in patients with asthma but their are some differences between these two long-acting beta(2)-agonists in vitro and in vivo. Formoterol has a greater potency and intrinsic activity than salmeterol, which can become especially apparent at higher doses than that clinically recommended, and in contracted bronchi. Long-term use of long-acting beta(2)-agonists can induce tolerance, which can be partially reversed with corticosteroids. Long-acting beta(2)-agonists have some anti-inflammatory effects in vitro, but data in vivo are less convincing. Compared with doubling the dose of inhaled corticosteroids, the addition of inhaled long-acting beta(2)-agonists to inhaled corticosteroids improves symptom control in patients with asthma and reduces both the exacerbation rate of asthma and hospital admission rate. No enhanced airway responsiveness or loss of perception of dyspnea has been observed with the use of inhaled long-acting beta(2)-agonists. Monotherapy with long-acting beta(2)-agonists is not recommended.

Salmeterol HFA is as effective as salmeterol CFC in children and adults with persistent asthma

In accordance with the Montreal Protocol 1987, initiatives to phase out and replace ozone-depleting chlorofluorocarbon (CFC) propellants with non-ozone-depleting propellants in metered-dose inhalers (MDIs) in the treatment of asthma and chronic obstructive pulmonary disease are underway. In view of this, two multi-centre, randomised, parallel-group, double-blind studies were conducted to compare the safety and efficacy of salmeterol xinafoate delivered by an MDI using the hydrofluoroalkane (HFA) 134a propellant with the licensed CFC formulation (Serevent) in asthmatic populations of children (4-11 years) and adults (12 years). Patients on a stable dose of inhaled corticosteroids with a scope for improvement based on mean morning peak expiratory flow (PEF) and symptoms were randomised to receive salmeterol HFA MDI 50 microg twice daily or salmeterol CFC MDI 50 microg twice daily for 12 weeks. The primary efficacy variable was mean morning PEF and secondary variables included other lung function parameters, symptom scores, use of relief medication and safety assessments. The difference between the treatments in adjusted mean morning PEF (salmeterol HFA-salmeterol CFC) were 2.5 and -3.2 L/min for per-protocol populations of children and adults, respectively. The lower limit of 95% confidence intervals for both populations was within the pre-defined limit (-15 L/min) set for non-inferiority. Similar results were observed in intent-to-treat (ITT) populations. In children, the two formulations resulted in a lack of any statistically significant difference in secondary efficacy parameters. A significant difference at endpoint in clinic forced expiratory volume in 1s was reported in favour of the HFA formulation in the adult population, although the magnitude of this effect was not considered clinically significant. The incidences of adverse events (AEs) were similar for both formulations and populations, and no safety concerns were generated. Together these data demonstrate salmeterol HFA MDI to be as effective as salmeterol CFC MDI in adults and children.

A benefit-risk assessment of inhaled long-acting beta2-agonists in the management of obstructive pulmonary disease

The two inhaled long-acting beta2-adrenoceptor agonists, salmeterol and formoterol, have been studied extensively since their introduction in the early 1990s. In this review we consider the evidence for their efficacy and safety in adults with asthma and chronic obstructive pulmonary disease (COPD), by reviewing long-term prospective studies in which these drugs have been compared with placebo or an alternative bronchodilator. We have also assessed safety, including data from postmarketing surveillance studies and case-control studies using large databases. In patients with asthma, salmeterol and formoterol increase lung function, reduce asthmatic symptoms and improve quality of life when compared with placebo. Both drugs protect against exercise-induced asthma, although some tolerance develops with regular use. Tolerance to the bronchodilator effects of formoterol has also been seen, although this is small and most of the beneficial effects are maintained long-term. Both drugs have been shown to reduce asthma exacerbations but only in studies in which most patients were taking an inhaled corticosteroid. Adding a long-acting beta2-agonist provided better control than increasing the dose of inhaled corticosteroid in several studies. Long-acting beta2-agonists also provide better asthma control than use of regular short-acting beta2-agonists and theophylline. Their relative efficacy compared with leukotriene antagonists is uncertain as yet. Formoterol appears to be at least as safe and effective as a short-acting beta2-agonist when used on an 'as required' basis. In patients with COPD, both salmeterol and formoterol offer improved lung function and reduced COPD symptoms compared with placebo, and quality of life has been improved in some studies. Some tolerance to the bronchodilating effect of salmeterol was seen in one study. Most studies have not found a significant reduction in exacerbations in COPD. Both drugs have provided greater benefit than ipratropium bromide or theophylline; there are limited data on tiotropium bromide. The long-acting beta2-agonists cause predictable adverse effects including headache, tremor, palpitations, muscle cramps and a fall in serum potassium concentration. Salmeterol can also cause paradoxical bronchospasm. There is some evidence that serious adverse events including dysrhythmias and life-threatening asthma episodes can occur; however, the incidence of such events is very low but may be increased in patients not taking an inhaled corticosteroid. Salmeterol 50 microg twice daily and formoterol 12 microg twice daily are effective and safe in treating patients with asthma and COPD. Higher doses cause more adverse effects, although serious adverse events are rare.

Benefit-risk assessment of long-acting beta2-agonists in asthma

The use of a regular long-acting beta2-adrenoceptor agonists (beta2-agonists; LABA) is now established in asthma guidelines as the preferred option for second-line controller therapy in addition to inhaled corticosteroids. This has been driven by data showing beneficial effects of LABAs on exacerbation rates, in turn suggesting a putative corticosteroid-sparing effect. As LABAs are devoid of any clinically meaningful anti-inflammatory activity in vivo, their effects on exacerbations are presumably due to a diurnal stabilising effect on airway smooth muscle. LABAs have marked effects on symptoms and lung function, and this may make it difficult to assess anti-inflammatory control with inhaled corticosteroids when used in a combination inhaler such as fluticasone propionate/salmeterol or budesonide/formoterol. The use of fixed-dose combination inhalers is in many respects counter-intuitive to conventional teaching regarding flexible dosage titration with inhaled corticosteroids. It would therefore seem prudent first to gain optimal control of inflammation with inhaled corticosteroids before considering adding a LABA. Increasing the dosage of inhaled corticosteroids will have a relatively greater effect on exacerbations than on symptoms and lung function, whereas the converse applies when adding a LABA. Another option is to add a leukotriene receptor antagonist, which confers additional anti-inflammatory activity and is as effective on exacerbations as adding a LABA. Despite in vitro and ex vivo data showing a ligand-independent effect of LABAs on glucocorticoid receptor activation, clinical data do not indicate any relevant synergy between LABAs and inhaled corticosteroids when used together in the same inhaler. In particular, there is no evidence of potentiation by LABAs of the in vivo anti-inflammatory activity of inhaled corticosteroids that would suggest any genuine corticosteroid-sparing activity. Nonetheless, the data support the additive effects of inhaled corticosteroids and LABAs when used together due to their separate effects on inflammation and smooth muscle, respectively. Tolerance with LABAs is a predictable pharmacological phenomenon that occurs despite concomitant therapy with inhaled corticosteroids. Moreover, cross-tolerance also develops to short-acting beta2-agonists used for protection against bronchoconstrictor stimuli as a result of LABA-induced down-regulation, desensitisation and prolonged occupancy of beta2-adrenoceptors. The exact role of beta2-adrenoceptor polymorphism in determining tolerance with LABAs requires further prospective clinical studies evaluating long-term effects on outcomes such as exacerbations in patients with relevant genotypes and haplotypes. The next decade will provide challenging issues for clinicians with respect to defining further the role of LABAs as add-on controller therapy, particularly in evaluating the long-term effects of combination inhalers on inflammatory outcomes and airway remodelling.

[Pharmacological action and clinical aspects of salmeterol]

Previous systemic beta(2) agonists such as procatrol tablets and tulobuterol patch were developed in Japan to address nocturnal symptoms and maintenance of lung function in asthmatic patients. Salmeterol, a potent and highly selective in beta(2) adrenocepter agonist with a duration of action greater than 12 h, was developed to provide long duration of bronchodilation with binding to a non-active site in the beta(2)-adrenocepter. Salmeterol is administrated via dry power inhalation and clinical studies have showed it has a good efficacy and a good safety profile, similar to inhaled steroids. Indeed, many clinical studies showed that salmeterol demonstrated better efficacy than long-acting beta(2)-agonist oral bronchodilators, theophyllines, and leukotriene-receptor antagonists in asthmatic patients and anticholinergic agents and theophyllines in COPD patients. Salmeterol will provide clinical benefits for Japanese asthma and COPD patients.

Effect of salmeterol xinafoate on lung mucociliary clearance in patients with asthma

Lung mucociliary clearance is impaired in stable asthma. The long-acting beta2-agonist salmeterol has been shown in vitro to cause a significant increase in ciliary beat frequency. It seemed possible therefore that salmeterol may also have a favourable effect on lung mucociliary transport in asthmatic patients. Fourteen patients with asthma participated in a double-blind, placebo-controlled, crossover study to assess the effect of 2 weeks of treatment with salmeterol MDI (50 microg b.d.) on lung mucociliary clearance. The 11 patients who completed the study (seven males, four females) had a mean +/- SE age of 50 +/- 4 years, % predicted FEV1 of 74 +/- 8% and a tobacco consumption history of 13 +/- 7 pack-years (seven non-smokers, four exsmokers). Lung mucociliary transport was measured by a radioaerosol technique. Pulmonary function indices (FEV1, FVC, and PEF) were significantly improved on salmeterol relative to placebo. The main radioaerosol finding was a significant increase in the penetration of radioaerosol into the lung with 24-h radioaerosol rising from 40 +/- 5% on placebo to 49 +/- 4% (P < 0.01) on salmeterol. Despite this increased penetration, a slight favourable change occurred in tracheobronchial aerosol clearance. This study demonstrates that 2 weeks salmeterol treatment influences deposition of particles within the lung by increasing airway patency and indicates a beneficial effect of MDI salmeterol on lung mucociliary clearance.

Addition of salmeterol to fluticasone propionate treatment in moderate-to-severe asthma

This study was designed to determine whether the benefit of adding salmeterol was superior to doubling the dose of fluticasone propionate (FP) over 6 months, compared to a control group who remained on a lower dose of FP. The multi-centre, double-blind, parallel group study involved 496 symptomatic asthmatic patients with a history of exacerbations on 500-800 micrograms (microg) inhaled corticosteroids (ICS) twice daily (b.d.) in a broadly representative group of 100 hospitals and general practices in six countries. Two doses of FP--250 microg b.d. (FP250) or 500 microg b.d. (FP500)--were compared with the lower dose of FP plus a long-acting beta2-agonist, salmeterol 50 microg b.d. (SM/FP250). Patients symptomatic on the run-in dose of FP250 alone formed the control group in the treatment period. Over 6 months, SM/FP250 significantly improved mean morning peak expiratory flow rates (amPEF) by 42.1 l/min, more than twice the improvement achieved with either dose of FP alone. SM/FP250 also resulted in more symptom-free days and nights (P < 0.002) and days and nights with no relief medication (P < 0.001). The number of severe exacerbations was low: 3, 6 and 8% in the SM/FP250, low- and high-dose FP groups, respectively. This study confirms that adding salmeterol to low-dose inhaled FP offers greater improvements than either maintaining or doubling the dose of FP. Significant benefit was gained from adding salmeterol in a group of patients who appeared to have been at the top of their steroid dose-response curve receiving FP250. There was no evidence of tolerance and a low incidence of exacerbations in all treatment groups.

Inhalation therapy for bronchial asthma: strategies and targets

Bronchial asthma is associated with symptoms, reversible airflow obstruction, airway hyper-responsiveness and inflammation along large and small airways. Inhalation therapy with bronchodilators (relievers) and anti-inflammatory agents (controllers) forms the basis of treatment for most patients with asthma of different severities. Conventionally, therapeutic efficacy is assessed on the basis of improvements in symptoms and lung function. However, airway hyper-responsiveness as a primary outcome may change therapeutic strategies. There are problems associated with this concept which need to be addressed, such as the heterogeneity of airway inflammation in the asthmatic lung. The goals for inhalation therapy should be to determine the site of airway inflammation for each degree of asthma severity, to improve inhaler technology, ensuring that the drug can reach the site of inflammation, and to improve compliance. New inhalers need to do the following: contain appropriate therapeutic agents; have particle dimensions small enough to be deposited in distal airways; and minimize the effects of incorrect inhalation and low compliance.

Inhaled long acting beta agonists for stable chronic asthma

BACKGROUND

Asthma is a common respiratory disease among both adults and children and short acting inhaled beta-2 agonists are used widely for 'reliever' bronchodilator therapy. Long acting beta-2 agonists were introduced as prospective 'symptom controllers' in addition to inhaled corticosteroid 'preventer' therapy (ICS).

OBJECTIVES

This review aimed to determine the benefit or detriment on the primary outcome of asthma control with the regular use of long acting inhaled beta-2 agonists compared with placebo.

SEARCH STRATEGY

We carried out searches using the Cochrane Airways Group trial register, most recently in October 2002. We searched bibliographies of identified RCTs for additional relevant RCTs and contacted authors of identified RCTs for other published and unpublished studies.

SELECTION CRITERIA

All randomised studies of at least two weeks duration, comparing a long acting inhaled beta-agonist given twice daily with a placebo, in chronic asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers performed data extraction and study quality assessment independently. We contacted authors of studies for missing data.

MAIN RESULTS

Eighty five studies met the inclusion criteria, 56 parallel group and 29 cross over design. Salmeterol xinafoate was used as long acting agent in 60 studies and formoterol fumarate in 25. The treatment period was two to four weeks in 32 studies, and 12 to 52 weeks in 53 studies. 34 study groups used concurrent inhaled corticosteroid treatment, 21 studies did not permit their use and 35 permitted either inhaled corticosteroid or cromones. There were significant advantages to long acting beta-2 agonist treatment compared to placebo for a variety of measurements of airway calibre including morning peak expiratory flow (PEF) (weighted mean difference (WMD) 26.78 L/min 95%CI 20.36 to 33.20), evening PEF (WMD 19.17 L/min 95%CI 11.63 to 26.73). They were associated with significantly fewer symptoms, less use of rescue medication and higher quality of life scores. The risk of exacerbation was lower in adults using regular inhaled corticosteroids.

REVIEWER'S CONCLUSIONS

Long acting beta-2 agonists are effective in the control of chronic asthma, and the evidence supports their use in addition to inhaled corticosteroids, as emphasised in current guidelines. Further research is needed on their use in children under 12 and in mild asthmatics not taking ICS.

Effects of beta2-agonists on airway tone and bronchial responsiveness

In evaluating the clinical consequences of beta(2)-agonist therapy, it is important to consider the possibility of reduced asthma control and increased bronchial responsiveness with regular or long-term use. Some studies have noted reductions in protective effects but not complete loss of protection with short-acting beta(2)-agonist therapy. These reductions vary, depending on the use of nonspecific, indirect, or immunologic challenges, but it appears there is a greater loss of protective effect against indirect stimuli. Tachyphylaxis to the bronchodilatatory effects of long-acting beta(2)-agonists appears to be minimal. Individuals homozygous for arginine at locus 16 of the beta(2)-adrenergic receptor gene have a decline in pulmonary function during beta(2)-agonist use, and they are at greater risk of asthma exacerbations during beta(2)-agonist therapy than patients with other genotypes. Important questions for further research are whether small differences in tachyphylaxis and bronchoprotection have relevant clinical effects and to what extent tachyphylaxis and tolerance to bronchoprotection are caused by pharmacogenetic interactions.

Effects of beta2-agonists on resident and infiltrating inflammatory cells

beta(2)-adrenergic receptors are present on inflammatory cells such as mast cells, monocytes, eosinophils, T-lymphocytes, and neutrophils implicated in the pathophysiology of respiratory disease. Short-acting beta(2)-agonists (eg, albuterol) and long-acting beta(2)-agonists (eg, salmeterol, formoterol) inhibit cell activation, inflammatory mediator release, and cell recruitment and survival mechanisms in vitro, with evidence of cellular specificity in response. In some cases, these effects can be observed in vivo, particularly with the long-acting agents. Reductions in inflammatory cell numbers, activation status in airway tissue, and inflammatory markers in sputum, bronchoalveolar lavage fluid, and blood have been reported after administration of clinical doses of salmeterol and formoterol. The inflammatory cell inhibitory activity of beta(2)-agonists is increased in the presence of corticosteroids, resulting in additive and/or synergistic effects on mediator release, adhesion molecule expression, and cellular proliferation. In vivo, the combination of long-acting beta(2)-agonist and corticosteroid exhibits an anti-inflammatory effect greater than that of the agonist alone, as well as a reduction in airway vascularity, a component of remodeling, that corticosteroids alone cannot produce.

Antagonism of long-acting beta2-adrenoceptor agonism

The established place of regular long-acting beta2-adrenoceptor agonists at step 3 in asthma management guidelines has evolved as a consequence of evidence showing additive effects of salmeterol and formoterol on exacerbation rates, resulting in a putative inhaled corticosteroid sparing effect. There is however, evidence to show that although long-acting beta2-adrenoceptor agonists facilitate using a lower dose of inhaled corticosteroid, this may occur at the expense of suboptimal anti-inflammatory control. This is likely to be the case especially with fixed dose combination inhalers where it is not possible to properly titrate anti-inflammatory therapy with inhaled corticosteroids without also inadvertently overtreating with unnecessarily high doses of long-acting beta2-adrenoceptor agonists. Most patients with mild to moderate persistent asthma can be adequately controlled on monotherapy with inhaled corticosteroid in low or medium dosage, which is considerably cheaper than concomitant use of a long-acting beta2-adrenoceptor agonist. Subsensitivity to long-acting beta2-adrenoceptor agonists is a predictable pharmacological phenomenon which occurs despite concomitant inhaled corticosteroid therapy and occurs more readily for bronchoprotective than bronchodilator effects. Subsensitivity of salbutamol protection against bronchoconstrictor stimuli occurs in patients receiving concomitant long-acting beta2-adrenoceptor agonists, which may be due to beta2-adrenoceptor down-regulation or prolonged receptor occupancy. Prospective large scale long-term studies are required to further define the clinical relevance of beta2-adrenoceptor polymorphisms, to look at clinical control outcomes as well as propensity for subsensitivity. It would therefore make more sense to first of all optimize the dose of anti-inflammatory therapy with inhaled corticosteroid and to then consider adding a long-acting beta2-adrenoceptor agonist for patients who are poorly controlled.

Evaluation of long-term efficacy of an asthma education programme in an out-patient clinic

The aim of the present study was to evaluate long-term efficacy of a patient education programme in an asthma out-patient clinic. The study included two groups. Educational group consisted of 25 patients who were given special education for one year. Usual care group included 27 patients who were not given special education. All patients were evaluated after 3 years follow-up period. Mean per cent asthma knowledge score (KS%), mean per cent demonstration score (DS%), daytime and nighttime symptom scores, Aas score, and pulmonary function tests were measured. The asthma-quality-of-life assessment was performed. The rate of application to emergency room and admission to hospital for last 1 year had been calculated. KS% was higher in educational group than in usual care group (P < 0.001). Daytime score was 0.3 +/- 0.6 in educational group and was 0.8 +/- 1.2 in usual care group (P = 0.08). Nighttime symptom score was found to be 0.5 +/- 0.9 and 0.9 +/- 1.3, respectively (P = 0.07). Usual care group had higher Aas score compared to educational group (P = 0.048). The total score of quality of life was 197.1 +/- 17.8 in educational group and was 176.7 +/- 33.7 in usual care group (P = 0.009). While none of the patients had emergency room application and hospital admission in educational group, seven patients had 21 emergency room application (P = 0.01) and four patients had four hospital admissions in usual care group. Additional short-acting inhaled beta-2 agonist usage was found lower in the educational group (P = 0.068). In conclusion, proper drug use and usual care of patients are not sufficient for asthma treatment. Patient education is an important component of therapy in asthma patients. For a life with optimum standards, in addition to these factors, patient education must be accepted first by doctors and then by patients.

Regular treatment with long acting beta agonists versus daily regular treatment with short acting beta agonists in adults and children with stable asthma

BACKGROUND

Selective beta-adrenergic agonists for use in asthma are: short acting (2-6 hours) and long acting (>12 hours). There has been little controversy about using short acting beta-agonists intermittently, but long acting beta-agonists are used regularly, and their regular use has been controversial.

OBJECTIVES

To determine the benefit or detriment of treatment with regular short- or long acting inhaled beta-agonists in chronic asthma.

SEARCH STRATEGY

A search was carried out using the Cochrane Airways Group register. Bibliographies of identified RCTs were searched for additional relevant RCTs. Authors of identified RCTs were contacted for other published and unpublished studies.

SELECTION CRITERIA

All randomised studies of at least two weeks duration, comparing a long acting inhaled beta-agonist given twice daily with any short acting inhaled beta-agonist of equivalent bronchodilator effectiveness given regularly in chronic asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers performed data extraction and study quality assessment independently. Authors of studies were contacted for missing data.

MAIN RESULTS

31 studies met the inclusion criteria, 24 of parallel group and 7 cross over design. Salmeterol xinafoate was used as long acting agent in 22 studies and formoterol fumarate in 9. Salbutamol was the short acting agent used in 27 studies and terbutaline in 5. The treatment period was over 2 weeks in 29 studies, and at least 12 weeks in 20. 25 studies permitted a variety of co-intervention treatments, usually inhaled corticosteroid or cromones. One study did not permit inhaled corticosteroid. Long acting beta-agonists were significantly better than short acting for a variety of lung function measurements including morning PEF (Weighted Mean Difference (WMD) 33 l/min 95% CI 25, 42) or evening PEF (WMD 26 l/min 95% CI 18, 33); and had significantly lower scores for day and night time asthma symptom scores and percentage of days and nights without symptoms. They were also associated with a significantly lower use of rescue medication both during the day and night. Risk of exacerbations was not different between the two types of agent, but most studies were of short duration which limits the power to test for such differences.

REVIEWER'S CONCLUSIONS

Long acting inhaled beta-agonists have advantages across a wide range of physiological and clinical outcomes for regular treatment.

Efficacy of inhaled budesonide and oral theophylline in asthmatic subjects

The aim of present study was to evaluate clinical, functional, and anti-inflammatory effects of inhaled budesonide and oral theophylline treatments in patients with mild to moderate asthma. The study included 38 patients. After a 10-day run-in period, the patients were randomly assigned into two groups. Group 1 received inhaled budesonide (Pulmicort Turbuhaler) 800 microg/day for 4 weeks. Group 2 received oral theophylline (Talotren tablets, 200 mg twice daily) for 4 weeks. Inhaled budesonide therapy was accompanied by a significant decrease in serum interleukin (IL)-5 levels (p < 0.0005) and blood, sputum, and nasal eosinophil counts (p < 0.005). It produced a significant reduction in daytime (p < 0.01) and nighttime (p < 0.005) symptom scores and an increase in morning (p < 0.005) and evening (p < 0.05) peak expiratory flow (PEF) and forced expiratory volume in I sec (FEV1) values (p < 0.01). Theophylline therapy was associated with a significant decrease in blood (p < 0.02) and nasal (p < 0.01) eosinophil counts and serum IL-5 levels (p < 0.01). It resulted in significant improvements in daytime and nighttime symptom scores (p < 0.05), and morning PEF and FEV1 values (p < 0.05). These changes were more significant in group I than in group 2. There was no statistically significant difference between the two groups with respect to post-treatment values. Our results confirm the role of inhaled corticosteroids in the treatment of asthma and are consistent with the recommendation that theophylline exerts an anti-inflammatory effect. Further studies should be conducted to determine long-term benefits of theophylline.

Evidence-based guideline on the primary care management of asthma

This is an updated version of the first North of England Asthma Guideline (1,2) and summarizes the full guideline. (3) This paper presents all the recommendations within the guideline and, where these are new or substantially altered from the original version, it also presents a summary of the supporting evidence. The aims and methods of development (summarized in Box 1) of this guideline are unchanged from the original version, to which readers are directed for more detail. The research questions raised during the development of this guideline are shown in Box 2.

Effectiveness and safety of salmeterol in nonspecialist practice settings

STUDY OBJECTIVES

To evaluate the effectiveness and safety of inhaled salmeterol in patients managed in nonspecialist practice settings.

DESIGN

A randomized, double-blind, 6-month, parallel-group study involving 253 centers.

SETTING

Primarily nonspecialist practices (n = 232).

PATIENTS

A total of 911 subjects (417 men; 494 women) who met American Thoracic Society asthma criteria were enrolled and randomized to treatment with either twice-daily salmeterol aerosol (50 microg; n = 455) or matching placebo twice daily (n = 456). Both groups were allowed to take salbutamol as needed. All subjects were previously treated with anti-inflammatory maintenance therapy that was continued throughout the study.

MEASUREMENTS AND RESULTS

The primary outcome variable was the proportion of subjects with serious asthma exacerbations defined as an exacerbation requiring hospitalization, emergency department visit, or use of prednisone during the treatment period. A total of 712 subjects competed the study. There was no significant difference in the proportion of subjects experiencing serious exacerbations between the salmeterol and placebo groups (20.8% vs 20.9%, respectively; p = 0.935; power > 88%). Peak expiratory flow was significantly higher in the salmeterol group (398 L/min vs 386 L/min for placebo; p < 0.01). Median daily use of salbutamol was two inhalations for the salmeterol group and three inhalations for placebo (p < 0.001). The proportion of subjects sleeping through the night was significantly higher in the salmeterol group (74%) as compared to placebo (68%; p = 0.028).

CONCLUSIONS

Salmeterol treatment is effective in subjects typically cared for in the primary-care setting and does not increase the frequency of severe exacerbations.

Advair: combination treatment with fluticasone propionate/salmeterol in the treatment of asthma

Several classes of medications are available for the treatment of asthma, and often they must be taken concurrently to achieve asthma control. Based on the understanding of asthma as an inflammatory disease, the National Heart Lung and Blood Institute guidelines provide a stepwise approach to pharmacologic therapy. Corticosteroid therapy, principally inhaled corticosteroid (ICS) therapy, is considered the most effective anti-inflammatory treatment. In cases of moderate-to-severe persistent asthma, the addition of a second long-term control medication to ICS therapy is one recommended treatment option. A combination-product inhaler (Advair, Seretide) was developed to treat both the inflammatory and bronchoconstrictive components of asthma by delivering a dose of the ICS, fluticasone propionate, and a dose of the long-acting beta2-adrenergic (LABA) bronchodilator, salmeterol. The Advair Diskus is available in 3 strengths of fluticasone propionate (100, 250, and 500 microg) and a fixed dose (50 microg) of salmeterol. Combination treatment with both ICS and LABA provides greater asthma control than increasing the ICS dose alone, while at the same time reducing the frequency and perhaps the severity of exacerbations. Furthermore, salmeterol added to ICS therapy provides superior asthma control compared with the addition of leukotriene modifiers or theophylline. The superior control is likely a consequence of the complementary actions of the drugs when taken together, including the activation of the glucocorticoid receptor by salmeterol. By combining anti-inflammatory treatment with a long-acting beta2-agonist in a single inhaler (1 inhalation twice daily), physicians can provide coverage for both the inflammatory and bronchoconstrictive aspects of asthma without introducing any new or unexpected adverse consequences. The most common drug-related adverse events were those known to be attributable to the constituent medications (ICS therapy and/or LABA therapy). Although the benefits of combined ICS plus LABA therapy can be achieved with separate inhalers, the convenience of the combination product may improve patient adherence and may therefore reduce the morbidity of asthma.

Comparison of powder and aerosol formulations of salmeterol in the treatment of asthma

BACKGROUND

The efficacy and safety of the aerosol metered-dose inhaler (MDI) formulation of salmeterol for asthma symptoms have been established. Recently, salmeterol has been introduced as a micronized powder formulation administered via a breath-activated multidose powder inhaler (Diskus).

OBJECTIVE

A multicenter, randomized, double-blind, double-dummy, parallel-group, placebo-controlled study involving 498 adolescents and adults with mild-to-moderate asthma was conducted to compare the efficacy and safety of salmeterol powder 50 microg twice daily via Diskus, salmeterol aerosol 42 microg twice daily via MDI, and placebo.

METHODS

Patients were randomized to one of the three treatment groups for 12 weeks. Efficacy was assessed by serial measurements of forced expiratory volume in one second (FEV1) over 12 hours, daily peak expiratory flow (PEF), self-rated asthma symptom scores, nighttime awakenings, and supplemental albuterol use. Safety of each treatment was evaluated by monitoring vital signs, electrocardiograms, Holter monitoring, and occurrence of adverse events.

RESULTS

As compared with placebo, both salmeterol powder and aerosol produced significant improvement in FEV1 and PEF and decreased nighttime awakenings and supplemental albuterol use. There were no significant differences in the efficacy of the two salmeterol formulations. The magnitude of improvement in pulmonary function was undiminished over the 12-week study. Both formulations of salmeterol were well tolerated, with safety profiles not significantly different from placebo.

CONCLUSION

Results of this study indicate that salmeterol, administered either as a powder 50 microg twice daily via Diskus or as an aerosol 42 microg twice daily via MDI, produces clinically significant and comparable improvement in pulmonary function and is well tolerated in patients with mild-to-moderate persistent asthma.

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.

Asthma exacerbations during first therapy with long acting beta 2-agonists

Long-acting beta 2-agonists (LBA) have become an important therapeutic strategy in the treatment of asthma. There is, however, debate whether LBA increase the risk of asthma exacerbations (AE). We studied whether the risk of AE was increased in patients starting LBA therapy and whether the risk was associated with severity. Patients, aged 5-49 years, who were firstly prescribed LBA between 1992 and 1995, and who had at least two consecutive prescriptions of LBA, were selected from the PHARMO-RLS database. The exposure period was the interval between the first and last dispensing of the first exposure episode. The year before the onset was the control period. Single short courses of oral glucocorticosteroids or antibiotics were used as proxy indicators for AE. Severity indicators, assessed in the 6 months before initiation of LBA, were used to classify patients' severity. A total of 788 patients met the inclusion criteria (men: 45.1%, median age: 35). The incidence rate of AE increased significantly (p < 0.001) with severity from 1.7 to 2.4 and 1.1 to 2.7 AE per person year in index and control period, respectively. The risk was merely elevated among patients who start LBA therapy without being treated with other anti-asthma drugs before (RR 1.4, 95% CI 1.0-2.2). First starters of LBA showed no overall change in incidence of AE when compared with the year before starting treatment. A total of 6.9% of patients used LBA as step-one therapy. These patients suffer, in contrast to the whole population, a 40% increased risk of having AE. Although this could be due to confounding, we recommend being reluctant to prescribe LBA to patients who have not been treated before with other anti-asthma drugs.

A six-month, placebo-controlled comparison of the safety and efficacy of salmeterol or beclomethasone for persistent asthma

BACKGROUND

There is a paucity of data comparing the long-term safety and efficacy of long-acting inhaled beta2-agonists versus low-dose inhaled corticosteroids in the treatment of asthma.

OBJECTIVE

To compare the safety and efficacy of salmeterol xinafoate, beclomethasone dipropionate (BDP), and placebo over a 6-month treatment period in patients with persistent asthma.

METHODS

Salmeterol (42 microg twice daily), BDP (84 microg four times daily), or placebo was administered via metered-dose inhaler to 386 adolescent and adult inhaled corticosteroid-naive patients in a randomized, double-blind, double-dummy, parallel-group study. Eligible patients demonstrated a forced expiratory volume in 1 second (FEV1) from 65% to 90% of predicted values. Pulmonary function, symptom control, frequency of asthma exacerbations, bronchial hyperresponsiveness (BHR) to methacholine challenge, and adverse events were assessed.

RESULTS

There were few statistically significant differences between the two active treatments over 6 months of therapy. Asthma symptoms and lung function were significantly improved with both salmeterol and BDP compared with placebo (changes from baseline in FEV1 of 0.28 L (SE = 0.04) and 0.23 L (SE = 0.04), respectively, compared with 0.08 L (SE = 0.04); P < or = .014). There were no significant differences among the treatment groups with respect to the distribution of asthma exacerbations over time. Both salmeterol and BDP significantly reduced BHR compared with placebo (P < or = .033; changes from baseline of 1.29 (SE = 0.26) and 1.42 (SE = 0.24) doubling doses at 6 months, respectively, compared with 0.24 (SE = 0.29) doubling dose for placebo). No rebound effect in BHR was seen upon cessation of any of the three treatment regimens. There were no clinically important differences in the safety profiles among the three treatments.

CONCLUSIONS

Both salmeterol and BDP are effective and well-tolerated when administered for 6 months to inhaled corticosteroid-naive patients with persistent asthma.

Long-term cardiovascular safety of salmeterol powder pharmacotherapy in adolescent and adult patients with chronic persistent asthma: a randomized clinical trial

STUDY OBJECTIVES

This study investigates the long-term cardiovascular safety of salmeterol powder vs placebo in adolescent and adult patients with mild persistent asthma.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled, parallel-group study.

SETTING

Eighteen US clinical centers.

PATIENTS

Three hundred fifty-two patients (> or = 12 years) with mild persistent asthma (duration > or = 6 months) requiring pharmacotherapy; with FEV1 of 70 to 90% of predicted and without abnormal ECG/continuous ambulatory ECG (Holter).

INTERVENTIONS

Randomized to twice-daily salmeterol powder (50 microg) or placebo via breath-actuated device for 52 weeks. Backup albuterol was available to control asthma symptoms.

MEASUREMENTS AND RESULTS

Cardiovascular safety was regularly assessed by 12-lead ECG with a 15-s lead II rhythm strip, 24-h continuous ambulatory ECG (Holter) monitoring, serial vital sign measurements, and review of adverse cardiovascular events. No deaths occurred during the study. No clinically significant between-group differences were observed in pulse rate, ECG QTc interval, median number of ventricular or supraventricular ectopic events, incidence of ventricular ectopic couplets and runs, or incidence of > 100 ventricular or supraventricular ectopic events in 24 h. No clinically significant between-group differences were observed in arterial BP or incidence of adverse cardiovascular events. Salmeterol was well tolerated throughout the 52-week study period, with a cardiovascular safety profile similar to that of placebo.

CONCLUSIONS

Long-term, twice-daily pharmacotherapy with salmeterol powder is safe and is not associated with unfavorable clinically significant changes in cardiac function or increases in cardiovascular adverse effects.

Nocturnal asthma: effect of salmeterol on quality of life and clinical outcomes

OBJECTIVE

To evaluate the effect of salmeterol on asthma-specific quality of life in patients experiencing significant nocturnal symptoms.

DESIGN

Randomized, double-blind, placebo-controlled, multicenter clinical trial.

SETTING

Allergy/respiratory care clinics.

PATIENTS

Nonsmokers > or = 12 years of age with nocturnal asthma symptoms on at least 6 of 14 days during screening and > or = 15% decrease in peak expiratory flow (PEF) from baseline on nocturnal awakening at least once during screening.

INTERVENTIONS

Salmeterol, 42 microg, or placebo twice daily. Patients were allowed to continue theophylline, inhaled corticosteroids, and "as-needed" albuterol.

MEASUREMENTS AND RESULTS

Outcome measures included Asthma Quality of Life Questionnaire (AQLQ) global and individual domain scores, FEV1, PEF, nighttime awakenings, asthma symptoms, and supplemental albuterol use. Mean change from baseline for the global and domain AQLQ scores was significantly greater (p < or = 0.005) with salmeterol compared with placebo. At week 12, salmeterol significantly (p < 0.001 compared with placebo) increased mean change from baseline in FEV1, morning and evening PEF, percentage of symptom-free days, percentage of nights with no awakenings due to asthma, and the percentage of days and nights with no supplemental albuterol use. Significant improvements in PEF were observed after treatment with salmeterol regardless of concomitant treatment with theophylline (p < 0.05).

CONCLUSIONS

These results provide evidence that validates the role of salmeterol in improving quality of life in patients with moderate persistent asthma who exhibited nocturnal asthma symptoms and supports the efficacy of salmeterol compared with that of placebo (ie, "as-needed" albuterol).

Evaluation of the efficacy of a hospital-based asthma education programme in patients of low socioeconomic status in Hong Kong

BACKGROUND

Good asthma control requires optimal medical treatment in conjunction with appropriate self-management. In the West, the effectiveness of patient education on improving self-management has been well documented. However, data amongst Asian populations are lacking. We performed a pilot study to evaluate the efficacy of a hospital based education programme aimed at improving self-management skills and reducing morbidity in a Chinese population with low socioeconomic status and education level.

METHODS

Our asthma education programme was a low-cost programme conducted in essence by specialist respiratory nurses. Patients attending our asthma clinic were instructed during a two-hour educational session on the pathophysiology of asthma, its potential triggers, the appropriate use of medications including proper inhaler techniques, and the self-management of their disease. These instructions were reinforced by video sessions at subsequent outpatient clinic attendance when patients' inhaler and peak flow techniques were checked by the same nurses and their self-management plan re-examined by the attending physicians. Asthma knowledge, inhaler technique, FEV1 and peak expiratory flow (PEF), and patients' self-rating of their asthma were determined at baseline, 6 months and 1 year after the intervention. Morbidity was assessed by the numbers of hospitalizations, unscheduled visits to family physicians and accident and emergency department attendance, courses of oral steroid used and days off work or school at baseline and 1 year.

RESULTS

Two hundred and thirty patients were recruited for the study, 83% completing the entire assessment period. The group demonstrated significant improvements in lung function: the mean FEV1 +/- SD increased from 63.6 +/- 20.6% of predicted values at baseline to 68.5 +/- 22.3% at 6 months and 68.6 +/- 22.8% at 1 year (P < 0.05), and the mean PEF +/- SD increased from 64.6 +/- 23.0% of predicted values at baseline to 75.4 +/- 27.0% at 6 months and 76.8 +/- 24.5% at 1 year(P < 0.001). There were also significant improvements in inhaler technique (P < 0.01), asthma knowledge (P < 0.001), patients' self-rating of their asthma (P < 0.05), and reductions in the numbers of hospitalizations (P < 0.01), visits to family physicians (P < 0.001) and accident and emergency department attendance (P < 0.001) during the study period. Patients with moderate to severe asthma as defined by an FEV1 of < 80% of predicted values were most likely to benefit from the programme.

CONCLUSIONS

We conclude that patient education is likely to be an essential component in the holistic approach to the management of asthma even amongst Asian populations of low socioeconomic status and education level. Further studies using randomised controlled trials are necessary to consolidate our findings.

[What is new in pediatric pneumology?]

Have been selected for this review: 1) the recent and impressive development of high-resolution and spiral CT scan in pediatric thoracic imaging; 2) the emerging of new and promising therapies for asthma (long acting inhaled beta 2-agonists, leukotriene antagonists, anti-IgE monoclonal antibodies); 3) the multifactorial origin of asthma in childhood; 4) the development of thoracoscopic surgery, a minimal-invasive approach beneficial in numerous circumstances.

Bronchodilator responses to salbutamol using diskhaler versus metered-dose inhaler

In adults inhaling salbutamol via metered-dose inhalers (MDls) 200 microg doses are recommended, but with diskhalers the manufacturer advocates 400 rather than 200 microg doses. To assess this advice, a partially double-blind, placebo-controlled salbutamol dose response, crossover study (also incorporating MDI doses) was conducted in 12 mild/moderate asthmatics. After active treatment, mean peak expiratory flow rate (PEFR) increments yielded no clinically or statistically significant differences; compared to placebo, respective median differences in PEFR increments (95% Cls) were 10 (-10, 50), 20 (0, 50), and 15 (0, 30) following 400 and 200 microg via diskhalers and 200 microg via MDls. Diskhalers are a suitable alternative for patients with poor MDI technique, but the use of 400 rather than 200 microg salbutamol doses is not supported by evidence.

Addition of salmeterol versus doubling the dose of beclomethasone in children with asthma. The Dutch Asthma Study Group

Studies in adults revealed that addition of salmeterol to a moderate dose of inhaled corticosteroid resulted in better symptom control and higher PEF compared with doubling the dose of inhaled corticosteroid. The aim of this three group study was to compare the effects of a moderate dose of beclomethasone, the same dose of beclomethasone with salmeterol, and a doubling dose of beclomethasone on lung function and symptoms in children with moderate asthma. A total of 177 children already treated with inhaled corticosteroids, were randomized in a double-blind parallel study either to salmeterol 50 microg twice daily (BDP400+salm), beclomethasone 200 microg twice daily (BDP800), or placebo (BDP400) in addition to beclomethasone 200 microg twice daily. No significant differences between groups were found in FEV1, PD20 methacholine, symptom scores, and exacerbation rates after 1 yr. Salmeterol resulted in slightly better PEF in the first months of treatment. FEV1, and PD20 methacholine significantly improved in all groups. After 1 yr mean changes in FEV1, percent predicted were 4.3% (95% CI 1.3; 7.2), 5.8% (95% CI 2.9; 8.7), and 4.3% (95% CI 2.1; 6.5) for BDP400+salm, BDP800, and BDP400, respectively. Changes in airway responsiveness were 0.60 (95% CI 0.05; 1.14), 1.30 (95% CI 0.73; 1. 87), and 0.80 (95% CI 0.33; 1.27) doubling doses. Growth was significantly slower in the BDP800 group. We conclude that no additional benefit was found of adding either salmeterol or more beclomethasone to a daily dose of 400 microg beclomethasone in this group of children with excellent compliance of medication.

Efficacy of salmeterol xinafoate powder in children with chronic persistent asthma

BACKGROUND

The efficacy and safety of salmeterol powder have not previously been evaluated in children with asthma in the United States.

OBJECTIVE

The efficacy and safety of salmeterol powder versus placebo were compared in children between the ages of 4 and 11 years with chronic persistent asthma.

METHODS

A randomized, double-blind, placebo-controlled, parallel group trial was performed at 11 clinical centers. Two hundred seven patients were randomly assigned to receive 50 microg salmeterol powder or placebo (and albuterol as needed) twice daily via a breath-actuated device for 12 weeks. Twelve-hour serial pulmonary function assessments were conducted on day 1 and at week 12. Daily recordings of morning and evening peak expiratory flow (PEF), supplemental albuterol use, asthma symptoms, and nocturnal awakenings were assessed.

RESULTS

On day 1 and at week 12, weighted mean percent of predicted PEF (P < .001, day 1 and P=.008, week 12) and weighted mean forced expiratory volume in one second (P < .001, day 1 and week 12) were significantly higher at all timepoints evaluated over the 12-hour postdosing period in patients treated with salmeterol powder compared with placebo. Overall reductions in supplemental albuterol use and mean asthma symptom scores were also significantly greater in children administered salmeterol compared with placebo (P=.004 and P=.006, respectively). The frequency of adverse events was similar in the two treatment groups.

CONCLUSION

Salmeterol powder (50 microg twice daily) is effective and safe in producing bronchodilation and relieving symptoms in children with chronic persistent asthma during 12 weeks of treatment.

Effect of salmeterol treatment on nitric oxide level in exhaled air and dose-response to terbutaline in children with mild asthma

The aim of this study was to investigate whether regular treatment with inhaled salmeterol modifies the dose-response curve to the inhaled short-acting beta2-agonist terbutaline or affects the concentration of nitric oxide (NO) in exhaled air of children with asthma. Twenty-two children aged 7 to 15 years (mean = 11.6 years) with mild asthma were treated with inhaled 50 microg salmeterol twice daily or placebo for 3 weeks in a randomized double-blind cross-over study. These treatments were followed by treatment with inhaled 200 microg budesonide twice daily for 3 weeks. On the last day of each period, NO level was measured in exhaled air and a cumulative dose-response experiment with terbutaline (cumulative dose: 1,475 microg) was performed. Baseline lung functions after salmeterol treatment were significantly higher than baseline after placebo (P + 0.05). Salmeterol treatment flattened out the dose-response curve to terbutaline such that higher doses of terbutaline were required to produce the same degree of bronchodilation (ED50 for FEV1 was increased by an estimated factor of 70 (95% CI: 0.8-6307) and ED50 for FEF25-75 by a factor of 41 (95% CI: 6.7-254); P < 0.05). NO levels were unaffected by salmeterol treatment (12.7 ppb; placebo = 10.7 ppb), but were significantly reduced during budesonide therapy (5.2 ppb; P < 0.001). The corresponding maximal NO levels were 19.5 (placebo), 22.9 (salmeterol), and 9.4 ppb (budesonide). We conclude that 3 weeks treatment with salmeterol does not affect NO levels in exhaled air, but it significantly changes the dose-response curve to terbutaline.

An overview of nine clinical trials of salmeterol in an asthmatic population

In an attempt to establish the protection afforded by regular salmeterol use against induced bronchoconstriction in asthmatic patients, a meta-analysis was conducted on nine double-blind clinical trials that fulfilled the inclusion criteria. In each trial, subjects were randomly assigned to receive either salmeterol 50 micrograms twice daily or a comparator (placebo or salbutamol). Two hundred and twenty-five asthmatic subjects had at least one PC20 or PD20 (histamine or methacholine concentration or dose producing 20% fall in forced expiratory volume in 1 s) measurement recorded within 1 h to 16 weeks after the first dose, and up to 31 days after the last dose, of medication. One hour after the first dose of salmeterol, there was a 3.5-fold increase in doubling dose compared to baseline. Within 12 h of the first dose, the level of protection was 1.5 doubling doses, and protection was maintained at 0.5-1.5 doubling doses over 16 weeks' treatment. This level of protection was maintained for up to 60 h after the last dose. At no time during the washout period did the level of protection fall below zero. Salmeterol afforded significantly greater protection at all time points during the treatment period than comparator agents, but there was no significant difference during the washout period. In conclusion, salmeterol affords protection against bronchoconstrictor stimuli, and any reduction in this bronchoprotective effect occurred during the first few days of treatment. During long-term salmeterol treatment, there was maintained significant protection that showed no evidence of attenuation after 16 weeks' treatment. Furthermore, there was no evidence of rebound deterioration in bronchial responsiveness after cessation of salmeterol treatment.

Long-acting inhaled beta2-agonists in asthma therapy

OBJECTIVE

To review the pharmacology of the long-acting inhaled beta2-agonists, salmeterol and formoterol, summarize results of their clinical trials, evaluate their safety records, and discuss their roles in the treatment of asthma.

DATA SOURCES

Preclinical and clinical studies involving salmeterol or formoterol were identified by a MEDLINE search, weekly computerized literature updates, and manual searches. Studies of satisfactory quality were chosen for review.

DATA SYNTHESIS

Salmeterol and formoterol are potent and selective beta2-adrenoceptor agonists with durations of action >12 h. Their major differences are that formoterol has a rapid onset of action and is a partial agonist of high intrinsic efficacy, whereas salmeterol has a delayed onset and is a partial agonist of low intrinsic efficacy. Twice daily use of either drug results in improved lung function, reduced symptoms, and a better quality of life. These agents protect against exercise-induced asthma for 12 h and eliminate nighttime awakening in most patients. Limited tolerance develops, especially to their bronchoprotective effects, but their improvement of lung function is sustained.

CONCLUSIONS

Regular use of salmeterol or formoterol provides subjective and objective amelioration of asthma in patients experiencing excessive symptoms or physiologic impairment despite the regular administration of low doses of inhaled corticosteroids (equivalent to approximately 500 microg/d of beclomethasone). Intermittent use of either long-acting beta2-agonist can provide prolonged protection against exercise-induced asthma or nighttime symptoms. Patients should be instructed to continue taking inhaled steroids when long-acting beta2-agonists are administered on a regular schedule and to not take long-acting beta2-agonists between regularly scheduled doses. Used properly, they are effective and safe adjunctive agents in the treatment of asthma.

The efficacy and safety of salmeterol compared to theophylline: meta-analysis of nine controlled studies

The aim of this study was to compare the efficacy and safety of salmeterol vs theophylline in asthma management using meta-analysis of clinical trials. Nine clinical studies, containing a total of 1330 patients, met meta-analysis inclusion criteria: randomized, controlled study, minimum 2-week treatment duration with either salmeterol or theophylline. The main outcome measurements were morning and evening peak expiratory flow rate (PEFR), morning and evening symptom scores, use of salbutamol as rescue medication, and withdrawal from treatment for any cause. During the second week of treatment, salmeterol patients had a 10 l min-1 greater increase in mean morning PEFR from baseline than theophylline patients (P < 0.001). Similarly, in the second week, the increase in mean evening PEFR from baseline observed with salmeterol was significantly greater (P < 0.01) than that observed with theophylline. Salmeterol also produced a significantly greater increase in mean morning and evening PEFR than theophylline at weeks 3 and 4. Patients receiving salmeterol were free from daytime symptoms for a mean of 51% of days in the second week compared to 39% for theophylline patients (P < 0.001). Salmeterol patients experienced a mean of 63% symptom-free nights compared to 52% for theophylline patients (P < 0.001). Rescue medication with salbutamol was not required on 49% of days for salmeterol patients and 34% of days for theophylline patients. All results were maintained in the third and fourth weeks of treatment. Withdrawal and incidence of adverse events leading to withdrawal were significantly less frequent in patients receiving salmeterol (P < 0.001). Thus, this meta-analysis suggests that salmeterol has a superior safety and efficacy profile to theophylline in the management of symptoms of chronic asthma.

A comparison of regular salmeterol vs 'as required' salbutamol therapy in asthmatic children

In a multicentre, double-blind, randomized, parallel study, 426 asthmatic children aged 5-15 years old received salmeterol 50 micrograms b.i.d. or placebo b.i.d. via the Diskhaler. All patients had access to inhaled salbutamol to be used on an 'as required' (p.r.n.) basis for symptomatic relief. The study design comprised a 2-week baseline, a 12-month treatment period incorporating a 2-week 'off treatment' after 6 months, and a 2-week follow-up period at the end of the trial. At the end of 12 months of treatment with salmeterol, the adjusted change from baseline for morning and evening peak expiratory flow rate (PEF) was 56 and 47 l min-1, respectively, and this was significantly greater than placebo (P < 0.01; P < 0.05). Exacerbation rates did not differ between groups and results were not dependent upon concurrent inhaled steroid use. Neither treatment caused a change of > or = 1 doubling dose in PC20/PD20 either during or on stopping treatment. Treatment with regular salmeterol 50 micrograms b.i.d. over a 12-month treatment period provides a significant, rapid and well-maintained improvement in lung function without increasing bronchial reactivity or asthma exacerbation rates compared to p.r.n. salbutamol.

One year treatment with salmeterol compared with beclomethasone in children with asthma. The Dutch Paediatric Asthma Study Group

The aim of this study was to compare the effects of salmeterol and beclomethasone on lung function and symptoms in children with mild to moderate asthma. Sixty-seven children not treated with inhaled corticosteroids were randomized in a double-blind parallel study either to salmeterol 50 micrograms b.i.d. or beclomethasone 200 micrograms b.i.d. After one year, FEV1 significantly increased in the beclomethasone group, whereas in the salmeterol group there was a small reduction. Differences between groups were 14.2% predicted (p < 0.0001) and 7.0% predicted (p = 0.007) for pre- and postbronchodilator FEV1 values, respectively. PD20 methacholine decreased by 0.73 DD (p = 0.05) in the salmeterol group and increased by 2.02 DD (p < 0.0001) in the beclomethasone group. Morning and evening PEF and symptom scores improved in both groups, although more in the beclomethasone group. Asthma exacerbations, for which prednisolone was needed, were more frequent in the salmeterol group (17 versus two), as were the number of withdrawals due to exacerbations (six versus one). However, growth was significantly slower in the beclomethasone group (-0.28 SDS) compared with that in the salmeterol group (-0.03 SDS) (p = 0.001). We conclude that treatment with a moderate dose of beclomethasone is superior to salmeterol in children with mild to moderate asthma and recommend that salmeterol should not be used as monotherapy.

Salmeterol. A review of its pharmacological properties and clinical efficacy in the management of children with asthma

Salmeterol xinafoate is a selective beta 2-adrenoceptor agonist indicated for the maintenance treatment of adults and children with asthma. When administered as a dry powder or aerosol, salmeterol produces bronchodilation for at least 12 hours and protects against methacholine and exercise-induced bronchoconstriction. Salmeterol is not recommended for the treatment of acute exacerbations of asthma. Recent clinical studies have demonstrated the efficacy and tolerability of inhaled salmeterol in the management of asthma in children. Salmeterol improved symptom control and lung function more effectively than placebo or regularly administered salbutamol. In children who were symptomatic despite regular inhaled corticosteroid therapy, the addition of salmeterol to treatment produced a significant improvement in morning and evening peak expiratory flow and forced expiratory volume in 1 second, and a significant reduction in the incidence of asthma exacerbations compared with placebo. Notably, the long duration of action of salmeterol makes it particularly suitable for the prevention of nocturnal asthma symptoms and exercise-induced asthma (EIA) in children. Current data suggest that salmeterol should not be used as a substitute for corticosteroid therapy in children, but rather as an adjunct to therapy. Thus, salmeterol may be a suitable adjunct to therapy in children with asthma receiving inhaled corticosteroids. In addition, salmeterol also has a potentially important role in the prevention of EIA and nocturnal asthma symptoms.

The effect of salmeterol on nocturnal symptoms, airway function, and inflammation in asthma

STUDY OBJECTIVE

To determine the efficacy of salmeterol alone in a group of patients with moderate asthma with nocturnal worsening of symptoms.

DESIGN

Double-blind, randomized, placebo-controlled crossover study.

SETTING

Tertiary care hospital specializing in respiratory diseases.

PARTICIPANTS

Ten patients with nocturnal asthma.

INTERVENTIONS

Subjects were randomized to salmeterol, 100 micrograms twice daily, or placebo for 6 weeks with a 1-week washout between treatment periods. Symptoms, nocturnal awakenings, and beta 2-agonist use were recorded daily. Spirometry was performed at weeks 1 and 6 of each period at bedtime and at 4 AM, and methacholine challenge was performed at 4 AM followed by bronchoscopy with BAL. BAL fluid analysis included cell count and differential count, eosinophil cationic protein, Charcot-Leyden crystal protein, leukotriene B4, and thromboxane B2.

RESULTS

The percentage of nights with awakenings decreased significantly with salmeterol (69.8 +/- 8.7% vs 30.6 +/- 10.8% for placebo and salmeterol, respectively; p = 0.02). The percentage of 24-h days with supplemental inhaled beta 2-agonist use significantly decreased with salmeterol (85.9 +/- 9.4% vs 70.4 +/- 10.1% for placebo and salmeterol, respectively; p = 0.04). There were no significant differences in bronchial reactivity, 4 AM FEV1, overnight percentage change in FEV1, or indexes of airway inflammation.

CONCLUSIONS

Salmeterol alone improves the number of nocturnal awakenings and supplemental 24-h beta 2-agonist use in nocturnal asthma without significantly altering lung function and airway inflammation.

Airway subsensitivity with long-acting beta 2-agonists. Is there cause for concern?

Regular treatment with both long- and short-acting beta 2-agonists results in tolerance to their bronchoprotective effects, although the relevance of this phenomenon in terms of long term asthma control remains unclear. However, there appears to be no appreciable difference between the 2 long-active beta 2-agonists, salmeterol and formoterol, in their propensity to induce beta 2-adrenoceptor down-regulation and subsensitivity. The degree of subsensitivity appears to be somewhat greater with indirect stimuli such as exercise and allergen challenge, compared with direct stimuli such as histamine and methacholine. This loss of functional antagonism with long-acting beta 2-agonist therapy is partial and is not prevented by concomitant inhaled corticosteroid therapy. However, the protective effects of inhaled corticosteroids on their own appear to be additive to those of long-acting beta 2-agonists when both drugs are concomitantly administered in the long term. The subsensitivity to bronchoprotection may be of clinical relevance in terms of patients who are inadvertently exposed to indirect bronchoconstrictor stimuli such as allergens or exercise, suggesting that long-acting beta 2-agonists should not be taken on a regular basis for this particular indication. There is a greater tendency for bronchodilator subsensitivity to develop with longer-acting, than with shorter-acting beta 2-agonists, and this may reflect the longer duration of beta 2-adrenoceptor occupancy and consequent downregulation. As with the bronchoprotective effects of long-acting beta 2-agonists, the development of bronchodilator subsensitivity is only partial and occurs regardless of whether patients are taking concomitant inhaled corticosteroid therapy. The long-term bronchodilator action of the long-acting beta 2-agonist itself is maintained within the twice daily administration interval. However, subsensitivity occurs in relation to a blunted response to repeated doses of short-acting beta 2-agonists, as in the setting of an acute asthma attack. There is considerable inter-individual variability in the propensity for downregulation and subsensitivity, which is determined by genetic polymorphism of the beta 2-adrenoceptor. Current international asthma management guidelines suggest that long-acting beta 2-agonists should be used on a regular basis in patients who ware inadequately controlled on inhaled corticosteroid therapy, so the addition of long-acting beta 2-agonist therapy is an alternative to using higher doses of inhaled corticosteroids. There are, however, concerns that regular long-acting beta 2-agonists might result in masking of inadequately treated inflammation in patients receiving suboptimal inhaled corticosteroid therapy. Physicians should be aware of the airway subsensitivity that develops with long-acting beta 2-agonist therapy, and patients should be warned that they may have to use higher than conventional dosages of short-acting beta 2-agonists to relieve acute bronchoconstriction in order to overcome this effect. In patients receiving an optimised maintenance dose of inhaled corticosteroid, if long-acting beta 2-agonists are to be used on an as required basis, it would seem rational to use formoterol for this purpose, due to its faster onset of action than salmeterol.

A twelve-week comparison of salmeterol and salbutamol in the treatment of mild-to-moderate asthma: a Canadian multicenter study

BACKGROUND

A long-acting inhaled bronchodilator that is both well tolerated and effective could allow for improved control of both daytime and nighttime symptoms in patients with asthma who use frequent as-needed short-acting bronchodilators despite antiinflammatory treatment.

OBJECTIVE AND METHODS

We compared the efficacy and safety of inhaled salmeterol, 50 micrograms twice daily, with inhaled salbutamol, 200 micrograms four times daily, delivered through a metered-dose inhaler for 3 months in a multicenter, randomized, double-blind, parallel-group study of 228 patients (aged 12 to 76 years) with mild-to-moderate asthma.

RESULTS

A single morning dose of salmeterol produced improvement in FEV1 that was significantly greater (p < or = 0.012) than that produced by two doses of salbutamol (taken 6 hours apart) when patients were assessed 3 to 6 hours and 10 to 12 hours after the dose. This greater bronchodilation was present on day 1 of the study and after 4, 8, and 12 weeks of regular treatment. Over the 12 weeks, compared with salbutamol, salmeterol treatment was associated with a greater mean improvement in morning peak expiratory flow (35 L/min vs -3 L/min, p < 0.001), a higher percentage of days with no symptoms (29% vs 15%; p = 0.012), and a higher percentage of nights with no awakenings (14% vs -1%; p < 0.001). Adverse events were similar for both treatments.

CONCLUSIONS

In this study salmeterol, 50 micrograms twice daily, was well tolerated and more effective than salbutamol, 200 micrograms four times daily, in improving symptoms and lung function in patients with mild-to-moderate asthma.

Salmeterol tachyphylaxis in steroid treated asthmatic subjects

BACKGROUND

Tachyphylaxis to the protection afforded by salmeterol to broncho-constrictor stimuli after regular use has been described in patients with mild asthma not receiving inhaled corticosteroids. The present study was performed to investigate whether airway tachyphylaxis occurs in symptomatic asthmatic subjects receiving inhaled corticosteroids, the group for whom salmeterol is recommended in clinical practice.

METHODS

Thirty one adult patients with symptomatic chronic asthma who were receiving inhaled corticosteroids were randomised in a double blind manner and on a 2:1 basis to receive salmeterol 50 micrograms (n = 22) or placebo (n = 9) twice daily. Baseline forced expiratory volume in one second (FEV1) was measured during the run-in period, on day 0, and after four and eight weeks of regular treatment (following a 36 hour test drug washout period). Airway responsiveness to methacholine was measured one hour after administration of the test drug on these occasions. Diary cards were kept throughout the study and for a two week follow up period.

RESULTS

Baseline FEV1 was not significantly different between the treatment groups or between visits. There was significant bronchodilatation one hour after salmeterol administration at 0, four, and eight weeks. No significant tachyphylaxis of the bronchodilator action of salmeterol was seen. Protection against methacholine induced bronchoconstriction reduced from 3.3 doubling dilutions after the first dose of salmeterol to two doubling dilutions after four and eight weeks of regular treatment. Symptom scores and "rescue" salbutamol use were significantly reduced during salmeterol treatment and daytime improvements were maintained into the follow up period.

CONCLUSIONS

Inhaled corticosteroids did not prevent tachyphylaxis to the protection afforded by salmeterol to methacholine induced bronchoconstriction. The clinical significance, if any, of these findings remains to be defined.