Interactions between corticosteroids and beta2-agonists

Safety and Effectiveness of As-Needed Formoterol in Asthma Patients Taking Inhaled Corticosteroid (ICS)-Formoterol or ICS-Salmeterol Maintenance Therapy

BACKGROUND

As-needed low-dose inhaled corticosteroid (ICS)-formoterol reliever is recommended in patients with asthma prescribed maintenance ICS-formoterol. Clinicians often ask whether ICS-formoterol reliever can be used with other maintenance ICS-long-acting β2-agonists.

OBJECTIVE

To evaluate the safety and effectiveness of as-needed formoterol in patients taking maintenance ICS-formoterol or ICS-salmeterol from the RELIEF study.

METHODS

RELIEF (SD-037-0699) was a 6-month, open-label study that randomized 18,124 patients with asthma to as-needed formoterol 4.5 μg or salbutamol 200 μg on top of maintenance therapy. This post hoc analysis included patients on maintenance ICS-formoterol or ICS-salmeterol (n = 5436). The primary safety outcome was a composite of serious adverse events (SAEs) and/or adverse events leading to discontinuation (DAEs); the primary effectiveness outcome was time-to-first exacerbation.

RESULTS

For both maintenance groups and both relievers, similar numbers of patients had ≥1 SAE and/or DAE. In patients taking maintenance ICS-salmeterol, but not ICS-formoterol, significantly more non-asthma-related and nonserious DAEs occurred with as-needed formoterol versus as-needed salbutamol (P = .0066 and P = .0034, respectively). In patients taking maintenance ICS-formoterol, there was a significantly lower risk in time-to-first exacerbation with as-needed formoterol versus as-needed salbutamol (hazard ratio [HR]: 0.82, 95% confidence interval [CI]: 0.70, 0.95; P = .007). In patients taking ICS-salmeterol maintenance, time-to-first exacerbation was not significantly different between treatment arms (HR: 0.95, 95% CI: 0.84, 1.06; P = .35).

CONCLUSIONS

As-needed formoterol significantly reduced exacerbation risk compared with as-needed salbutamol when added to maintenance ICS-formoterol, but not to maintenance ICS-salmeterol. More DAEs were seen with ICS-salmeterol maintenance therapy plus as-needed formoterol. Further research is needed to assess whether this is relevant to as-needed combination ICS-formoterol.

Regular treatment with formoterol and an inhaled corticosteroid versus regular treatment with salmeterol and an inhaled corticosteroid for chronic asthma: serious adverse events

BACKGROUND

Asthma is characterised by chronic inflammation of the airways and recurrent exacerbations with wheezing, chest tightness, and cough. Treatment with inhaled steroids and bronchodilators can result in good control of symptoms, prevention of further morbidity, and improved quality of life. However, an increase in serious adverse events with the use of both regular formoterol and regular salmeterol (long-acting beta₂-agonists) compared with placebo for chronic asthma has been demonstrated in previous Cochrane Reviews. This increase was statistically significant in trials that did not randomise participants to an inhaled corticosteroid, but not when formoterol or salmeterol was combined with an inhaled corticosteroid. The confidence intervals were found to be too wide to ensure that the addition of an inhaled corticosteroid renders regular long-acting beta₂-agonists completely safe; few participants and insufficient serious adverse events in these trials precluded a definitive decision about the safety of combination treatments.

OBJECTIVES

To assess risks of mortality and non-fatal serious adverse events in trials that have randomised patients with chronic asthma to regular formoterol and an inhaled corticosteroid versus regular salmeterol and an inhaled corticosteroid.

SEARCH METHODS

We searched the Cochrane Airways Register of Trials, CENTRAL, MEDLINE, Embase, and two trial registries to identify reports of randomised trials for inclusion. We checked manufacturers' websites and clinical trial registers for unpublished trial data, as well as Food and Drug Administration (FDA) submissions in relation to formoterol and salmeterol. The date of the most recent search was  24 February 2021.

SELECTION CRITERIA

We included controlled clinical trials with a parallel design, recruiting patients of any age and severity of asthma, if they randomised patients to treatment with regular formoterol versus regular salmeterol (each with a randomised inhaled corticosteroid) and were of at least 12 weeks' duration.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion in the review, extracted outcome data from published papers and trial registries, and applied GRADE rating for the results. We sought unpublished data on mortality and serious adverse events from study sponsors and authors. The primary outcomes were all cause mortality and non-fatal serious adverse events. We chose not to calculate an average result from all the formulations of formoterol and inhaled steroid, as the doses and delivery devices are too diverse to assume a single class effect.

MAIN RESULTS

Twenty-one studies in 11,572 adults and adolescents and two studies in 723 children met the eligibility criteria of the review. No data were available for two studies; therefore these were not included in the analysis. Among adult and adolescent studies, seven compared formoterol and budesonide to salmeterol and fluticasone (N = 7764), six compared formoterol and beclomethasone to salmeterol and fluticasone (N = 1923), two compared formoterol and mometasone to salmeterol and fluticasone (N = 1126), two compared formoterol and fluticasone to salmeterol and fluticasone (N = 790), and one compared formoterol and budesonide to salmeterol and budesonide (N = 229). In total, five deaths were reported among adults, none of which was thought to be related to asthma. The certainty of evidence for all-cause mortality was low, as there were not enough deaths to permit any precise conclusions regarding the risk of mortality on combination formoterol versus combination salmeterol. In all, 201 adults reported non-fatal serious adverse events. In studies comparing formoterol and budesonide to salmeterol and fluticasone, there were 77 in the formoterol arm and 68 in the salmeterol arm (Peto odds ratio (OR) 1.14, 95% confidence interval (CI) 0.82 to 1.59; 5935 participants, 7 studies; moderate-certainty evidence). In the formoterol and beclomethasone studies, there were 12 adults in the formoterol arm and 13 in the salmeterol arm with events (Peto OR 0.94, 95% CI 0.43 to 2.08; 1941 participants, 6 studies; moderate-certainty evidence). In the formoterol and mometasone studies, there were 18 in the formoterol arm and 11 in the salmeterol arm (Peto OR 1.02, 95% CI 0.47 to 2.20; 1126 participants, 2 studies; moderate-certainty evidence). One adult in the formoterol and fluticasone studies in the salmeterol arm experienced an event (Peto OR 0.05, 95% CI 0.00 to 3.10; 293 participants, 2 studies; low-certainty evidence). Another adult in the formoterol and budesonide compared to salmeterol and budesonide study in the formoterol arm had an event (Peto OR 7.45, 95% CI 0.15 to 375.68; 229 participants, 1 study; low-certainty evidence). Only 46 adults were reported to have experienced asthma-related serious adverse events. The certainty of the evidence was low to very low due to the small number of events and the absence of independent assessment of causation. The two studies in children compared formoterol and fluticasone to salmeterol and fluticasone. No deaths and no asthma-related serious adverse events were reported in these studies. Four all-cause serious adverse events were reported: three in the formoterol arm, and one in the salmeterol arm (Peto OR 2.72, 95% CI 0.38 to 19.46; 548 participants, 2 studies; low-certainty evidence).

AUTHORS' CONCLUSIONS

Overall, for both adults and children, evidence is insufficient to show whether regular formoterol in combination with budesonide, beclomethasone, fluticasone, or mometasone has a different safety profile from salmeterol in combination with fluticasone or budesonide. Five deaths of any cause were reported across all studies and no deaths from asthma; this information is insufficient to permit any firm conclusions about the relative risks of mortality on combination formoterol in comparison to combination salmeterol inhalers. Evidence on all-cause non-fatal serious adverse events indicates that there is probably little to no difference between formoterol/budesonide and salmeterol/fluticasone inhalers. However events for the other formoterol combination inhalers were too few to allow conclusions. Only 46 non-fatal serious adverse events were thought to be asthma related; this small number in addition to the absence of independent outcome assessment means that we have very low confidence for this outcome. We found no evidence of safety issues that would affect the choice between salmeterol and formoterol combination inhalers used for regular maintenance therapy by adults and children with asthma.

Current Bronchodilator Responsiveness Criteria Underestimate Asthma in Older Adults

BACKGROUND

Asthma is common in older adults and is confirmed by demonstration of variable expiratory air-flow limitations, typically evaluated by spirometric assessment of bronchodilator responsiveness. However, many patients with clinically suspected asthma and documented air-flow obstruction do not exhibit a post-bronchodilator response that meets or exceeds current established guidelines. We investigated if extending the time from bronchodilator administration to assessment of bronchodilator response increases the yield of spirometry for the diagnosis of asthma in older adults.

METHODS

This was a cross-sectional study. The subjects were non-smokers, ≥ 60 y old, and with suspected asthma. Subjects were characterized as (1) those with a positive bronchodilator response on the 30-min post-bronchodilator spirometry, (2) those with a positive bronchodilator response on the 60-min post-bronchodilator spirometry, and (3) those without a positive bronchodilator response but with a positive methacholine challenge test. Factors associated with a late response to bronchodilator were evaluated by using bivariate analysis and by multivariate analysis by using a logistic regression model.

RESULTS

This study enrolled 165 subjects. Of these, 81 (49.1%) had a positive bronchodilator response on 30-min post-bronchodilator spirometry; 25 (15.2%) had a positive bronchodilator response on the 1-h post-bronchodilator spirometry; and 59 (35.8%) had no positive bronchodilator response but had a positive methacholine challenge test. On multivariable regression analysis, those with a higher baseline percentage of predicted FEV₁, higher scores on a standard asthma control test, and wheezing and/or cough after exercise were more likely to either have a late bronchodilator response or no bronchodilator response.

CONCLUSIONS

Our study showed that a late positive response to bronchodilator use was more common than previously presumed in older subjects with suspected asthma. Pulmonary function testing laboratories should consider routinely reassessing spirometry at 1 h after bronchodilator use if the earlier assessment did not reveal a significant response.

Benefit:Risk Profile of Budesonide in Obstructive Airways Disease

Airway inflammation is a major contributing factor in both asthma and chronic obstructive pulmonary disease (COPD) and represents an important target for treatment. Inhaled corticosteroids (ICS) as monotherapy or in combination therapy with long-acting β2-agonists or long-acting muscarinic antagonists are used extensively in the treatment of asthma and COPD. The development of ICS for their anti-inflammatory properties progressed through efforts to increase topical potency and minimise systemic potency and through advances in inhaled delivery technology. Budesonide is a potent, non-halogenated ICS that was developed in the early 1970s and is now one of the most widely used lung medicines worldwide. Inhaled budesonide's physiochemical and pharmacokinetic/pharmacodynamic properties allow it to reach a rapid and high airway efficacy due to its more balanced relationship between water solubility and lipophilicity. When absorbed from the airways and lung tissue, its moderate lipophilicity shortens systemic exposure, and its unique property of intracellular esterification acts like a sustained release mechanism within airway tissues, contributing to its airway selectivity and a low risk of adverse events. There is a large volume of clinical evidence supporting the efficacy and safety of budesonide, both alone and in combination with the fast- and long-acting β2-agonist formoterol, as maintenance therapy in patients with asthma and with COPD. The combination of budesonide/formoterol can also be used as an as-needed reliever with anti-inflammatory properties, with or without regular maintenance for asthma, a novel approach that is already approved by some country-specific regulatory authorities and currently recommended in the Global Initiative for Asthma (GINA) guidelines. Budesonide remains one of the most well-established and versatile of the inhaled anti-inflammatory drugs. This narrative review provides a clinical reappraisal of the benefit:risk profile of budesonide in the management of asthma and COPD.

Inhaled steroids with and without regular salmeterol for asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between use of beta₂-agonists and increased asthma mortality. Much debate has surrounded possible causal links for this association, and whether regular (daily) long-acting beta₂-agonists (LABAs) are safe, particularly when used in combination with inhaled corticosteroids (ICSs). This is an update of a Cochrane Review that now includes data from two large trials including 11,679 adults and 6208 children; both were mandated by the US Food and Drug Administration (FDA).  OBJECTIVES: To assess risks of mortality and non-fatal serious adverse events (SAEs) in trials that randomised participants with chronic asthma to regular salmeterol and ICS versus the same dose of ICS.

SEARCH METHODS

We identified randomised trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trials registers for unpublished trial data. We also checked FDA submissions in relation to salmeterol. The date of the most recent search was 10 October 2018.

SELECTION CRITERIA

We included parallel-design randomised trials involving adults, children, or both with asthma of any severity who were randomised to treatment with regular salmeterol and ICS (in separate or combined inhalers) versus the same dose of ICS of at least 12 weeks in duration.

DATA COLLECTION AND ANALYSIS

We conducted the review according to standard procedures expected by Cochrane. We obtained unpublished data on mortality and SAEs from the sponsors, from ClinicalTrials.gov, and from FDA submissions. We assessed our confidence in the evidence according to current GRADE recommendations.

MAIN RESULTS

We have included in this review 41 studies (27,951 participants) in adults and adolescents, along with eight studies (8453 participants) in children. We judged that the overall risk of bias was low for all-cause events, and we obtained data on SAEs from all study authors. All except 542 adults (and none of the children) were given salmeterol and fluticasone in the same (combination) inhaler.DeathsEleven of a total of 14,233 adults taking regular salmeterol and ICS died, as did 13 of 13,718 taking regular ICS at the same dose. The pooled Peto odds ratio (OR) was 0.80 (95% confidence interval (CI) 0.36 to 1.78; participants = 27,951; studies = 41; I² = 0%; moderate-certainty evidence). In other words, for every 1000 adults treated for 25 weeks, one death occurred among those on ICS alone, and the corresponding risk among those taking salmeterol and ICS was also one death (95% CI 0 to 2 deaths).No children died, and no adults or children died of asthma, so we remain uncertain about mortality in children and about asthma mortality in any age group.Non-fatal serious adverse eventsA total of 332 adults receiving regular salmeterol with ICS experienced a non-fatal SAE of any cause, compared to 282 adults receiving regular ICS. The pooled Peto OR was 1.14 (95% CI 0.97 to 1.33; participants = 27,951; studies = 41; I² = 0%; moderate-certainty evidence). For every 1000 adults treated for 25 weeks, 21 adults on ICS alone had an SAE, and the corresponding risk for those on salmeterol and ICS was 23 adults (95% CI 20 to 27).Sixty-five of 4229 children given regular salmeterol with ICS suffered an SAE of any cause, compared to 62 of 4224 children given regular ICS. The pooled Peto OR was 1.04 (95% CI 0.73 to 1.48; participants = 8453; studies = 8; I² = 0%; moderate-certainty evidence). For every 1000 children treated for 23 weeks, 15 children on ICS alone had an SAE, and the corresponding risk for those on salmeterol and ICS was 15 children (95% CI 11 to 22).Asthma-related serious adverse eventsEighty and 67 adults in each group, respectively, experienced an asthma-related non-fatal SAE. The pooled Peto OR was 1.15 (95% CI 0.83 to 1.59; participants = 27,951; studies = 41; I² = 0%; low-certainty evidence). For every 1000 adults treated for 25 weeks, five receiving ICS alone had an asthma-related SAE, and the corresponding risk among those on salmeterol and ICS was six adults (95% CI 4 to 8).Twenty-nine children taking salmeterol and ICS and 23 children taking ICS alone reported asthma-related events. The pooled Peto OR was 1.25 (95% CI 0.72 to 2.16; participants = 8453; studies = 8; I² = 0%; moderate-certainty evidence). For every 1000 children treated for 23 weeks, five receiving an ICS alone had an asthma-related SAE, and the corresponding risk among those receiving salmeterol and ICS was seven children (95% CI 4 to 12).

AUTHORS' CONCLUSIONS

We did not find a difference in the risk of death or serious adverse events in either adults or children. However, trial authors reported no asthma deaths among 27,951 adults or 8453 children randomised to regular salmeterol and ICS or ICS alone over an average of six months. Therefore, the risk of dying from asthma on either treatment was very low, but we remain uncertain about whether the risk of dying from asthma is altered by adding salmeterol to ICS.Inclusion of new trials has increased the precision of the estimates for non-fatal SAEs of any cause. We can now say that the worst-case estimate is that at least 152 adults and 139 children must be treated with combination salmeterol and ICS for six months for one additional person to be admitted to the hospital (compared to treatment with ICS alone). These possible risks still have to be weighed against the benefits experienced by people who take combination treatment.However more than 90% of prescribed treatment was taken in the new trials, so the effects observed may be different from those seen with salmeterol in combination with ICS in daily practice.

Bronchodilator responsiveness in wheezy infants predicts continued early childhood respiratory morbidity

OBJECTIVE

Spirometry including bronchodilator responsiveness is considered routine in the workup of asthma in older children. However, in wheezy infants the existence of bronchodilator responsiveness and its prognostic significance remain unclear.

METHODS

Infants (< 2 years) with chronic or recurrent wheezing or coughing were evaluated by infant pulmonary function testing (PFT). Maximal expiratory flow at the point of functional residual capacity (V̇maxFRC) was measured before and 20 minutes after salbutamol administration. Only infants with an obstructive profile (V̇maxFRC < 80% predicted) were included. The infants were divided into two groups with regard to whether or not a response to salbutamol was observed on PFT. A response was defined as a mean V̇maxFRC after salbutamol administration exceeding the upper confidence interval limit of individual pre-bronchodilator V̇maxFRC measurements. Follow-up data was gathered after a mean of 2 years.

MEASUREMENTS AND MAIN RESULTS

Sixty infants were included in the study of which 32 (53%) demonstrated responsiveness to bronchodilators. The infants in the responsive group had a significantly higher frequency of physician visits for wheezing than the non-responders (3.0 mean visits/yr vs. 1.5 respectively, P = 0.03), and had a higher likelihood of having received asthma medication in the last year of the follow-up period (84% vs. 50% respectively, RR: 1.68[1.10-2.56]). At the end of the follow-up period, more parents in the responsive group reported continued respiratory disease (71% vs. 22%, RR:3.21[1.30-7.95]).

CONCLUSIONS

Bronchodilator responsiveness can be demonstrated by infant PFT in infants with recurrent wheezing and can predict increased respiratory morbidity until 3 years of age.

Reconstitution of anti-allergic activities of PG102 derived from Actinidia arguta by combining synthetic chemical compounds

PG102, a water-soluble extract from an edible fruit, Actinidia arguta, has previously been shown to control various factors involved in allergy pathogenesis. It was investigated whether the original activities of PG102 could be reconstituted by mixing chemical compounds present in PG102. Six compounds present in PG102 were, individually or in the form of mixtures, tested for their effects on the expression of various Th2 cytokines and inflammatory mediators in the cell-based assay. Each chemical inhibited IL-4 expression to varying degrees. The chemical compounds were combined at a ratio present in PG102, resulting in two formulations, CQMIIH and CQM, consisting of all or the first three of the following chemicals, citric, quinic, and malic acids, myo-inositol, isoquercitrin, and 5-hydroxymethyl-2-furaldehyde. The mixtures reconstituted original activities of PG102 to a significant level. In the murine asthma model, CQM ameliorated asthmatic symptoms and significantly decreased the level of IgE and IL-5. The decreased phosphorylation of ERK1/2 was observed in cells and mice treated with PG102 and the mixtures. Our data indicated that the substantial portion of PG102's anti-allergic activities could be reconstituted, in vitro and in vivo, by mixing six chemical compounds, suggesting the possibility of developing a new type of anti-allergic agent. This approach may be useful for developing chemically defined functional products from complex botanical extracts.

Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta2-agonists and increases in asthma mortality. Much debate has surrounded possible causal links for this association and whether regular (daily) long-acting beta2-agonists are safe when used alone or in conjunction with inhaled corticosteroids. This is an updated Cochrane Review.

OBJECTIVES

To assess the risk of fatal and non-fatal serious adverse events in people with chronic asthma given regular formoterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

SEARCH METHODS

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data; Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was August 2012.

SELECTION CRITERIA

Controlled clinical trials with a parallel design were included if they randomly allocated people of any age and severity of asthma to treatment with regular formoterol and inhaled corticosteroids for at least 12 weeks.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Unpublished data on mortality and serious adverse events were obtained from the sponsors. We assessed the quality of evidence using GRADE recommendations.

MAIN RESULTS

Following the 2012 update, we have included 20 studies on 10,578 adults and adolescents and seven studies on 2788 children and adolescents. We found data on all-cause fatal and non-fatal serious adverse events for all studies, and we judged the overall risk of bias to be low.Six deaths occurred in participants taking regular formoterol with inhaled corticosteroids, and one in a participant administered regular inhaled corticosteroids alone. The difference was not statistically significant (Peto odds ratio (OR) 3.56, 95% confidence interval (CI) 0.79 to 16.03, low-quality evidence). All deaths were reported in adults, and one was believed to be asthma-related.Non-fatal serious adverse events of any cause were very similar for each treatment in adults (Peto OR 0.98, 95% CI 0.76 to 1.27, moderate-quality evidence), and weak evidence suggested an increase in events in children on regular formoterol (Peto OR 1.62, 95% CI 0.80 to 3.28, moderate-quality evidence).In contrast with all-cause serious adverse events, the addition of new trial data means that asthma-related serious adverse events associated with formoterol are now significantly fewer in adults taking regular formoterol with inhaled corticosteroids (Peto OR 0.49, 95% CI 0.28 to 0.88, moderate-quality evidence). Although a greater number of asthma-related events were reported in children receiving regular formoterol, this finding was not statistically significant (Peto OR 1.49, 95% CI 0.48 to 4.61, low-quality evidence).

AUTHORS' CONCLUSIONS

From the evidence in this review, it is not possible to reassure people with asthma that regular use of inhaled corticosteroids with formoterol carries no risk of increasing mortality in comparison with use of inhaled corticosteroids alone. On the other hand, we have found no conclusive evidence of serious harm, and only one asthma-related death was registered during more than 4200 patient-years of observation with formoterol.In adults, no significant difference in all-cause non-fatal serious adverse events was noted with regular formoterol with inhaled corticosteroids, but a significant reduction in asthma-related serious adverse events was observed in comparison with inhaled corticosteroids alone.In children the number of events was too small, and consequently the results too imprecise, to allow determination of whether the increased risk of all-cause non-fatal serious adverse events found in a previous meta-analysis on regular formoterol alone is abolished by the additional use of inhaled corticosteroids.We await the results of large ongoing surveillance studies mandated by the Food and Drug Administration (FDA) for more information. Clinical decisions and information provided to patients regarding regular use of formoterol have to take into account the balance between known symptomatic benefits of formoterol and the degree of uncertainty associated with its potential harmful effects.

Regular treatment with salmeterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta2-agonists and increased asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta2-agonists are safe. This is an updated systematic review.

OBJECTIVES

To assess the risk of mortality and non-fatal serious adverse events in trials which randomised patients with chronic asthma to regular salmeterol and inhaled corticosteroids in comparison to the same dose of inhaled corticosteroids.

SEARCH METHODS

We identified randomised trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trial registers for unpublished trial data. Food and Drug Administration (FDA) submissions in relation to salmeterol were also checked. The date of the most recent search is August 2012.

SELECTION CRITERIA

We included parallel design controlled clinical trials on patients of any age and severity of asthma if they randomised patients to treatment with regular salmeterol and inhaled corticosteroids (in separate or combined inhalers), and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

We conducted the review according to standard procedures expected by the Cochrane Collaboration. We obtained unpublished data on mortality and serious adverse events from the sponsors, and from FDA submissions. We assessed the quality of evidence according to GRADE recommendations.

MAIN RESULTS

We have included 35 studies (13,447 participants) in adults and adolescents, and 5 studies (1862 participants) in children in this review. We judged that the overall risk of bias was low, and we obtained data on serious adverse events from all studies. All except 542 adults (and none of the children) who were randomised to salmeterol were given fluticasone in the same (combination) inhaler.Seven deaths occurred in 6986 adults on regular salmeterol with inhaled corticosteroids (ICS), and seven deaths in 6461 adults on regular inhaled corticosteroids at the same dose. The difference was not statistically significant (Peto odds ratio (OR) 0.90; 95% confidence interval (CI) 0.31 to 2.60, moderate quality evidence). The risk of dying from any cause in adults on ICS was 10 per 10,000, and on salmeterol and ICS we would expect between 3 and 26 deaths per 10,000. No deaths were reported in 1862 children, and no deaths were reported to be asthma-related in adults or children.Non-fatal serious adverse events of any cause were reported in 167 adults on regular salmeterol with ICS, compared to 135 adults on regular ICS; again this was not a statistically significant increase (Peto OR 1.15; 95% CI 0.91 to 1.44, moderate quality evidence). The frequency of serious adverse events was 21 per 1000 in the adults treated with ICS and 24 per 1000 in those treated with salmeterol and ICS. The absolute difference in the risk of non-fatal serious adverse events was an increase of 3 per 1000, that was not statistically significant (risk difference (RD) 0.003; 95% CI -0.002 to 0.008).There were 6 of 930 children with serious adverse events on regular salmeterol with ICS, compared to 5 out of 932 on regular ICS: there was no significant difference between treatments (Peto OR 1.20; 95% CI 0.37 to 3.91, moderate quality evidence).Asthma-related serious adverse events were reported in 29 and 23 adults in each group respectively, a non-significant difference (Peto OR 1.12; 95% CI 0.65 to 1.94, moderate quality evidence), and only 1 asthma-related event was reported in children in each treatment group.

AUTHORS' CONCLUSIONS

We found no statistically significant differences in fatal or non-fatal serious adverse events in trials in which regular salmeterol was randomly allocated with ICS, in comparison to ICS alone at the same dose. Although 13,447 adults and 1862 children have now been included in trials, the frequency of adverse events is too low and the results are too imprecise to confidently rule out a relative increase in all cause mortality or non-fatal adverse events with salmeterol used in conjunction with ICS. However, the absolute difference between groups in the risk of serious adverse events was very small. We could not determine whether the increase in all cause non-fatal serious adverse events reported in the previous meta-analysis on regular salmeterol alone is abolished by the additional use of regular ICS. We await the results of large ongoing surveillance studies mandated by the FDA to provide more information. There were no asthma-related deaths and few asthma-related serious adverse events. Clinical decisions and information for patients regarding regular use of salmeterol have to take into account the balance between known symptomatic benefits of salmeterol and the degree of uncertainty and concern associated with its potential harmful effects.

Medical emergencies: pulmonary embolism and acute severe asthma

In this, the second of two articles covering specific medical emergencies, we discuss the definitions, epidemiology, pathophysiology, acute and chronic management of pulmonary embolus and acute severe asthma.

Regular treatment with formoterol for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-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 formoterol versus placebo or regular short-acting beta(2)-agonists.

SEARCH METHODS

We identified trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trial registers for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol. The date of the most recent search was January 2012.

SELECTION CRITERIA

We included controlled, parallel design clinical trials on patients of any age and severity of asthma if they randomised patients to treatment with regular formoterol 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. One author extracted outcome data and the second author checked them. We sought unpublished data on mortality and serious adverse events.

MAIN RESULTS

The review includes 22 studies (8032 participants) comparing regular formoterol to placebo and salbutamol. Non-fatal serious adverse event data could be obtained for all participants from published studies comparing formoterol and placebo but only 80% of those comparing formoterol with salbutamol or terbutaline.Three deaths occurred on regular formoterol and none on placebo; this difference was not statistically significant. It was not possible to assess disease-specific mortality in view of the small number of deaths. Non-fatal serious adverse events were significantly increased when regular formoterol was compared with placebo (Peto odds ratio (OR) 1.57; 95% CI 1.06 to 2.31). One extra serious adverse event occurred over 16 weeks for every 149 people treated with regular formoterol (95% CI 66 to 1407 people). The increase was larger in children than in adults, but the impact of age was not statistically significant. Data submitted to the FDA indicate that the increase in asthma-related serious adverse events remained significant in patients taking regular formoterol who were also on inhaled corticosteroids.No significant increase in fatal or non-fatal serious adverse events was found when regular formoterol was compared with regular salbutamol or terbutaline.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular formoterol, and this does not appear to be abolished in patients taking inhaled corticosteroids. The effect on serious adverse events of regular formoterol in children was greater than the effect in adults, but the difference between age groups was not significant.Data on all-cause serious adverse events should be more fully reported in journal articles, and not combined with all severities of adverse events or limited to those events that are thought by the investigator to be drug-related.

Modulation of 11β-hydroxysteroid dehydrogenase 1 by β2-adrenoceptor in the ischaemia-reperfused rat kidney

BACKGROUND

11β-Hydroxysteroid dehydrogenase Type 1 (11βHSD-1) amplifies intracellular levels of active glucocorticoids which possess protective effects against organ ischaemia and reperfusion (I/R). However, the mechanisms by which 11βHSD-1 is modified after a renal I/R challenge remain unclear. This study investigated the effect of β(2)-adrenoceptor (β(2)-AR) activation and the subsequent signalling pathways on renal 11βHSD-1 gene expression following renal I/R.

METHODS

Renal I/R was induced using 25 min of bilateral renal artery occlusion in 4-week-old Wistar rats followed by an intraperitoneal injection of various doses of adeno-β(2)-AR gene. Following renal I/R, kidneys, plasma and urine were collected to assay 11βHSD messenger RNA (mRNA) levels, β(2)-AR signalling cascades and renal function.

RESULTS

On the second day after the renal I/R challenge, there was a reduction in renal 11βHSD-1 mRNA levels associated with a decrease in stimulatory G protein α (Gsα) and adenylate cyclase-1 (ACY-1) in the kidney. The addition of the adeno-β(2)-AR gene resulted in greater increases in 11βHSD-1 mRNA and β(2)-AR-Gsα-ACY-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) activity in the kidney but had no effect on 11βHSD-2 mRNA or protein kinase C levels in the kidney.

CONCLUSIONS

Over-expression of β(2)-AR resulting from the gene delivery improved renal function and 11βHSD-1 production following renal I/R, which were actions exerted through the cAMP-PKA pathway. The stimulatory effect of functional β(2)-AR activation on renal 11βHSD-1 expression may offer a means of protection from renal I/R injury.

Asthma in swimmers: a review of the current literature

Asthma is common in many types of athletes, but its prevalence appears to be particularly high in swimmers. Long-term and acute exposure to swimming pool disinfectants has been shown to increase asthma risk in swimmers through inducing oxidative stress, which results in inflammation of the pulmonary epithelium and subsequent airway remodeling. Individuals with specific genotypes are more likely to develop asthma when exposed to inhaled irritants. Therefore, it is important for physicians to be knowledgeable about the risks associated with asthma in swimmers, as well as the diagnostic techniques and practices to reduce asthma symptoms.

beta2-Adrenergic receptor gene polymorphism is associated with mortality in septic shock

RATIONALE

The CysGlyGln haplotype of the beta(2)-adrenergic receptor gene (ADRB2) is functional and associated with altered responses to adrenergic agonists in patients with asthma. Whether this functional haplotype alters outcome in patients receiving adrenergic agonists in septic shock is unknown.

OBJECTIVES

To determine whether genetic variation of ADRB2 influences outcome in septic shock.

METHODS

Two cohorts of patients with septic shock were studied: a single center (St. Paul's Hospital [SPH]) cohort (n = 589) and the Vasopressin and Septic Shock Trial (VASST) cohort (n = 616). The A allele of the rs1042717 G/A polymorphism is in complete linkage disequilibrium with the CysGlyGln haplotype of ADRB2; therefore, rs1042717 was genotyped. Modulation by norepinephrine and salbutamol of IL-6 production by stimulated in vitro lymphoblastoid cells was measured by genotype.

MEASUREMENTS AND MAIN RESULTS

Patients who had the AA genotype of rs1042717 displayed increased 28-day mortality in SPH (adjusted hazard ratio, 2.23; 95% confidence interval, 1.33-3.72; P = 0.0022), and this result was replicated in VASST (adjusted hazard ratio 2.82; 95% confidence interval, 1.56-5.09; P = 0.0006). This genotypic effect was eliminated in patients treated with acute low-dose corticosteroids. In all patients, the AA genotype was associated with more organ dysfunction. Patients with the AA genotype had a higher heart rate (SPH; P < 0.05; VASST; P < 0.05) and required a higher norepinephrine dose over Days 1 through 3 (VASST; P < 0.05). The AA genotype was associated with decreased norepinephrine and salbutamol inhibition of IL-6 production by stimulated lymphoblastoid cells in vitro (P < 0.05).

CONCLUSIONS

The AA genotype of ADRB2 rs1042717, identifying homozygotes for the CysGlyGln haplotype, was associated with increased mortality and more organ dysfunction in septic shock.

Regular treatment with salmeterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-agonists and increased 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 with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

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 Food and Drug Administration (FDA) submissions in relation to salmeterol were also checked. The date of the most recent search was October 2008.

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 inhaled corticosteroids (in separate or combined inhalers), and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data were independently extracted by two authors. Unpublished data on mortality and serious adverse events were obtained from the sponsors, and from FDA submissions.

MAIN RESULTS

The review included 30 studies (10,873 participants) in adults and adolescents, and three studies (1,173 participants) in children. The overall risk of bias was low and data on serious adverse events were obtained from all studies.Six deaths occurred in 5,710 adults on regular salmeterol with inhaled corticosteroids, and five deaths in 5,163 adults on regular inhaled corticosteroids at the same dose. The difference was not statistically significant (Peto OR 1.05; 95% CI 0.32 to 3.47) and the absolute difference between groups in risk of death of any cause was 0.00005 (95% CI -0.002 to 0.002). No deaths were reported in 1,173 children, and no deaths were reported to be asthma-related.Non-fatal serious adverse events of any cause were reported in 134 adults on regular salmeterol with inhaled corticosteroids, compared to 103 adults on regular inhaled corticosteroids; again this was not a significant increase (Peto OR 1.17; 95% CI 0.90 to 1.52). The absolute difference in the risk of non-fatal serious adverse events was 0.003 (95% CI -0.002 to 0.009).There were three of 586 children with serious adverse events on regular salmeterol with inhaled corticosteroids, compared to four out of 587 on regular inhaled corticosteroids: there was no significant difference between treatments (Peto OR 0.75; 95% CI 0.17 to 3.31).Asthma-related serious adverse events were reported in 23 and 21 adults in each group respectively, a non-significant difference (Peto OR 0.95; 95% CI 0.52 to 1.73), and only one event was reported in children.

AUTHORS' CONCLUSIONS

No significant differences have been found in fatal or non-fatal serious adverse events in trials in which regular salmeterol has been randomly allocated with inhaled corticosteroids, in comparison to inhaled corticosteroids at the same dose. Although 10,873 adults and 1,173 children have been included in trials, the number of patients suffering adverse events is too small, and the results are too imprecise to confidently rule out a relative increase in all-cause mortality or non-fatal adverse events. It is therefore not possible to determine whether the increase in all-cause non-fatal serious adverse events reported in the previous meta-analysis on regular salmeterol alone is abolished by the additional use of regular inhaled corticosteroids. The absolute difference between groups in the risk of serious adverse events was small. There were no asthma-related deaths and few asthma-related serious adverse events. Clinical decisions and information for patients regarding regular use of salmeterol have to take into account the balance between known symptomatic benefits of salmeterol and the degree of uncertainty and concern associated with its potential harmful effects.

Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-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 when used alone or in conjunction with inhaled corticosteroids.

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 formoterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

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 Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was October 2008.

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 formoterol and inhaled corticosteroids, and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data were independently extracted by two authors. Unpublished data on mortality and serious adverse events were obtained from the sponsors.

MAIN RESULTS

The review included 14 studies on adults and adolescents (8,028 participants) and seven studies on children and adolescents (2,788 participants). Data on all cause fatal and non-fatal serious adverse events were found for all studies, and the overall risk of bias was low.Four deaths occurred on regular formoterol with inhaled corticosteroids, and none on regular inhaled corticosteroids alone. All the deaths were in adults, and one was reported to be asthma-related. The difference was not statistically significant.Non-fatal serious adverse events of any cause were very similar in adults [Peto Odds Ratio 0.99 (95% CI 0.74 to 1.33)], and an increase in events in children on regular formoterol was not statistically significant [Peto Odds Ratio 1.62 (95% CI 0.80 to 3.28)].Asthma related serious adverse events on formoterol were lower in adults [Peto Odds Ratio 0.53 (95% CI 0.28 to 1.00)] and although they were higher in children [Peto Odds Ratio 1.49 (95% CI 0.48 to 4.61)], this was not statistically significant.

AUTHORS' CONCLUSIONS

It is not possible, from the data in this review, to reassure people with asthma that inhaled corticosteroids with regular formoterol carries no risk of increasing mortality in comparison to inhaled corticosteroids alone as all four deaths occurred among 6,594 people using inhaled corticosteroids with formoterol. On the other hand, we have found no conclusive evidence of harm and there was only one asthma related death registered during over 3,000 patient year observation on formoterol. In adults, the decrease in asthma-related serious adverse events on regular formoterol with inhaled corticosteroids was not accompanied by a decrease in all cause serious adverse events. In children the number of events was too small, and consequently the results too imprecise, to determine whether the increase in all cause non-fatal serious adverse events found in the previous meta-analysis on regular formoterol alone is abolished by the additional use of inhaled corticosteroids. Clinical decisions and information for patients regarding regular use of formoterol have to take into account the balance between known symptomatic benefits of formoterol and the degree of uncertainty and concern associated with its potential harmful effects.

Regular treatment with formoterol 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 formoterol 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 Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was July 2008.

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 formoterol 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 were extracted by one author and checked by the second author. Unpublished data on mortality and serious adverse events were sought.

MAIN RESULTS

The review includes 22 studies (8,032 participants) comparing regular formoterol to placebo and salbutamol. Non-fatal serious adverse event data could be obtained for all participants from published studies comparing formoterol and placebo but only 80% of those comparing formoterol with salbutamol or terbutaline.Three deaths occurred on regular formoterol and none on placebo; this difference was not statistically significant. It was not possible to assess disease specific mortality in view of the small number of deaths. Non-fatal serious adverse events were significantly increased when regular formoterol was compared with placebo (Odds Ratio 1.57 [95% CI: 1.05 to 2.37]). One extra serious adverse event occurred over 16 weeks for every 179 people treated with regular formoterol [95% CI: 75 to 2022]. The increase was larger in children than in adults, but the impact of age was not statistically significant. Data submitted to the FDA indicates that the increase in asthma-related serious adverse events remained significant in patients taking regular formoterol who were also on inhaled corticosteroids.No significant increase in fatal or non-fatal serious adverse events was found when regular formoterol was compared with regular salbutamol or terbutaline.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular formoterol, and this does not appear to be abolished in patients taking inhaled corticosteroids. The effect on serious adverse events of regular formoterol in children was greater than the effect in adults, but the difference between age-groups was not significant.Data on all-cause serious adverse events should be more fully reported in journal articles, and not combined with all adverse events or limited to those events that are thought by the investigator to be drug-related.

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.

beta-Adrenergic receptor polymorphisms: relationship to the beta-agonist controversy and clinical implications

Aspects of the 'beta-agonist controversy' have recently re-emerged with the publication of data implicating the long-acting beta-agonist salmeterol in increased mortality from asthma. The reasons underlying the adverse effects of beta2-agonists as a class are unclear. Polymorphisms of the beta2 adrenoceptor (ADRB2), notably the variant associated with an arginine moiety at position 16 of the ADRB2 protein result in changes in in vitro receptor function. There is now consistent clinical evidence showing that, in vivo, patients with asthma harbouring the Arg-16 genotype may experience reduced lung function and an increased frequency of exacerbations when treated with regular short-acting beta-agonists. This may, in part, explain why beta-agonists have been associated with adverse outcomes in the past. ADRB2 genotyping of patients with severe or difficult-to-control asthma may shed light on a possible contributor to their clinical instability.

Anti-inflammatory functions of glucocorticoid-induced genes

There is a broad consensus that glucocorticoids (GCs) exert anti-inflammatory effects largely by inhibiting the function of nuclear factor kappaB (NFkappaB) and consequently the transcription of pro-inflammatory genes. In contrast, side effects are thought to be largely dependent on GC-induced gene expression. Biochemical and genetic evidence suggests that the positive and negative effects of GCs on transcription can be uncoupled from one another. Hence, novel GC-related drugs that mediate inhibition of NFkappaB but do not activate gene expression are predicted to retain therapeutic effects but cause fewer or less severe side effects. Here, we critically re-examine the evidence in favor of the consensus, binary model of GC action and discuss conflicting evidence, which suggests that anti-inflammatory actions of GCs depend on the induction of anti-inflammatory mediators. We propose an alternative model, in which GCs exert anti-inflammatory effects at both transcriptional and post-transcriptional levels, both by activating and inhibiting expression of target genes. The implications of such a model in the search for safer anti-inflammatory drugs are discussed.

Overcoming beta-agonist tolerance: high dose salbutamol and ipratropium bromide. Two randomised controlled trials

BACKGROUND

Asthmatics treated with long-acting beta-agonists have a reduced bronchodilator response to moderate doses of inhaled short acting beta-agonists during acute bronchoconstriction. It is not known if the response to higher doses of nebulised beta-agonists or other bronchodilators is impaired. We assessed the effect of long-acting beta-agonist treatment on the response to 5 mg nebulised salbutamol and to ipratropium bromide.

METHODS

Two double-blind, placebo-controlled, crossover studies of inhaled formoterol 12 mug twice daily in patients with asthma.High-dose salbutamol: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled methacholine to produce a 20% fall in FEV1. Salbutamol 5 mg was then administered via nebuliser and the FEV1 was monitored for 20 minutes. Ipratropium: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled 4.5% saline to produce a 20% fall in FEV1. Salbutamol 200 mug or ipratropium bromide 40 mug was then inhaled and the FEV1 was monitored for 30 minutes. Four study arms compared the response to each bronchodilator after formoterol and placebo. Analyses compared the area under the bronchodilator response curves, adjusting for changes in pre-challenge FEV1, dose of provocational agent and FEV1 fall during the challenge procedure.

RESULTS

The response to nebulised salbutamol was 15% lower after formoterol therapy compared to placebo (95% confidence 5 to 25%, p = 0.008). The response to ipratropium was unchanged.

CONCLUSION

Long-acting beta-agonist treatment induces tolerance to the bronchodilator effect of beta-agonists, which is not overcome by higher dose nebulised salbutamol. However, the bronchodilator response to ipratropium bromide is unaffected.