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

The beta-agonist controversy

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

Comparison of salmeterol with disodium cromoglycate in the treatment of adult asthma

BACKGROUND

Disodium cromoglycate and salmeterol, a long acting beta 2-agonist, achieve their therapeutic effects through different mechanisms but both are used as maintenance therapies in asthma.

OBJECTIVES

It was the purpose of this study to assess the comparative efficacy and safety of both drugs when used as prophylactic therapy for adults with symptomatic mild to moderate asthma.

METHODS

In this 8-week, double-blind, double-dummy, parallel group, multicenter study, 134 adult patients with a forced expiratory volume in one second (FEV1) ranging from 60% to 90% predicted, reversibility in FEV1 of greater than 15% and a total daily symptom score of at least 2 or a diurnal variation in peak expiratory flow (PEF) of greater than 15% on three of the seven days of the run-in period, were randomized to either salmeterol, 50 microgram twice daily (via metered-dose inhaler), or disodium cromoglycate, 20 mg four times daily (via Spinhaler), plus corresponding placebo. Approximately 50% of the total population were concurrently receiving inhaled corticosteroids.

RESULTS

Salmeterol was significantly better than disodium cromoglycate in improving both morning (mean difference between treatments = 31 L/min; P = .007) and evening PEF (mean difference between treatments = 29 L/min; P = .008). Both treatments were however, associated with significant improvement in FEV1, daytime and night-time symptoms score and use of rescue salbutamol (P < .001). Although salmeterol tended to produce greater improvement than disodium cromoglycate in all these parameters only the difference in rescue salbutamol achieved statistical significance (P = .021). Salmeterol was the preferred treatment of both the patients and the physicians (P = .002). Both treatments were well tolerated with a similarly low incidence of adverse event reports, the majority of which were related to underlying disease.

CONCLUSION

Salmeterol, 50 microgram twice daily, provides better control of symptomatic mild to moderate asthma than disodium cromoglycate, 20 mg four times daily.

Efficacy and safety of salmeterol in childhood asthma

In children with asthma, twice daily administration of salmeterol 25 micrograms, salmeterol 50 micrograms and salbutamol 200 micrograms were compared in two, 3-month, double-blind, parallel group studies, one using metered dose inhalers (MDIs), the other using dry powder inhalers (Diskhaler, DPIs). Both studies were continued for a further 9 months during which time exacerbation rates, lung function at the clinic and adverse events were monitored. Similarities in design and methodology of the two studies justified a combined analysis. Eight hundred and forty-seven asthmatic children aged between 4 and 16 (mean 10.1) years, requiring inhaled beta 2-agonist treatment were randomised to treatment. After a 2 week run-in when all bronchodilator therapy was withdrawn, 279 patients received salmeterol 25 micrograms bd, 290 patients salmeterol 50 micrograms bd and 278 patients salbutamol 200 micrograms bd. After 3 months' treatment the change from baseline in daily morning and evening peak expiratory flow (PEF) was significantly greater with salmeterol 50 micrograms bd than with salbutamol 200 micrograms bd (P < 0.001). Salmeterol 50 micrograms bd was also significantly better than salmeterol 25 micrograms bd at improving mean morning PEF (P = 0.017) but both treatments had a similar effect on evening PEF. Analysis of variance showed an interaction between baseline PEF less than 100% predicted normal value and treatment outcome. Analysis of this sub-set of patients with lower lung function revealed similar results to the total population although the improvements in PEF from baseline were greater. Data from both studies, showed that the improvement in lung function was maintained throughout 12 months' treatment. Patients receiving salmeterol 50 micrograms bd had significantly more symptom-free nights (P < 0.01) and a higher percentage of rescue bronchodilator-free days (P = 0.01). The incidence of asthma exacerbations was evenly distributed between the three treatment groups and there was no evidence of any change in the rate of occurrence of exacerbations over the 12 month period. Adverse events were no different across treatment groups or across age groups and were primarily related to the patients' disease state.

CONCLUSION

Salmeterol 50 micrograms bd is the appropriate dose for the treatment of children with mild to moderate asthma.

Efficacy of inhaled salmeterol in the management of smokers with chronic obstructive pulmonary disease: a single centre randomised, double blind, placebo controlled, crossover study

BACKGROUND

The acute response to bronchodilators in patients with chronic obstructive pulmonary disease (COPD) is modest; it has, however, been suggested that these patients may benefit from long term treatment.

METHODS

To investigate the efficacy of salmeterol in smokers with moderate to severe COPD a double blind, randomised, crossover comparison was performed between salmeterol (50 micrograms twice daily) and placebo in 63 patients with stable COPD (mean age 65 years). Prior to inclusion, all patients had a forced expiratory volume in one second (FEV1) of < 60% of predicted and an improvement in FEV1 of < 15% following 400 micrograms inhaled salbutamol. Patients received four weeks of therapy with each of the treatment regimens. Assessment of efficacy was made with recording of morning and evening peak expiratory flow rates (PEF), respiratory symptoms, and use of rescue salbutamol. FEV1 was measured before and after nebulised salbutamol prior to randomisation and at the end of each treatment period.

RESULTS

Morning PEF values were higher during the salmeterol than during the placebo period, although the mean treatment difference was small (12 l/min (95% confidence limits 6 to 17)). No difference in mean evening PEF values was found. Diurnal variation in PEF, assessed as the difference between the morning PEF and that of the previous evening, was more pronounced during the placebo than during the salmeterol period. The mean spirometric values (including reversibility in FEV1) obtained at the end of the two treatment periods were similar. Compared with placebo, treatment with salmeterol was associated with lower daytime and night time symptom scores and less use of rescue salbutamol both during the day and the night. The patients rated the treatment with salmeterol better than treatment with placebo.

CONCLUSIONS

This study shows that, compared with placebo, treatment with salmeterol produces an improvement in respiratory symptoms and morning PEF values in patients with moderate to severe COPD. Treatment with long acting beta agonists may therefore result in an improvement in functional status, even in patients suffering from apparently nonreversible obstructive pulmonary disease.

Inhaled salmeterol and albuterol in asthmatic patients receiving high-dose inhaled corticosteroids

Salmeterol may be useful in the treatment of asthmatic patients requiring high-dose inhaled steroids, and there have been debates about its anti-inflammatory action. We have compared the efficacy and effects on serum inflammatory markers, including soluble interleukin 2R (sIL-2R), eosinophil cationic protein (ECP), and tryptase of salmeterol and albuterol in 20 patients with moderate to severe asthma who were all receiving high-dose inhaled corticosteroids and inhaled beta 2-agonist on demand. After a 2-week run-in period, they received, in a randomized, crossover, double-blind and placebo-controlled manner, either salmeterol, 50 micrograms twice a day, or albuterol 400 micrograms, four times a day, from a powder inhaler during two 2-week treatment periods, separated by a 2-week washout. Compared with albuterol, salmeterol treatment was associated with better morning and mean peak expiratory flow (p = 0.013 and 0.016, respectively), less daytime and nocturnal symptoms (p = 0.008 and 0.01, respectively), reduced requirement of rescue albuterol (p = 0.04), and better efficacy rating by patients (p = 0.04). However, serum concentration of sIL-2R was significantly higher during regular albuterol treatment (p = 0.014) but no differences were seen in the concentrations of ECP and tryptase between the two treatment periods. We conclude that inhaled salmeterol, 50 micrograms twice daily, confers a better control of asthma than albuterol, 400 micrograms four times daily, in patients with moderate to severe disease, and the latter treatment may be associated with increased T-lymphocyte activation.

A 4-week comparison of salmeterol and terbutaline in adult asthma

This was a 4-week, open-label, parallel-group study designed to compare the efficacy and safety of the long-acting inhaled bronchodilator, salmeterol, with the established inhaled bronchodilator, terbutaline, in the treatment of patients with mild to moderate asthma. A total of 243 adult patients was randomized to receive treatment with either salmeterol 50 micrograms bd via a Diskhaler (Glaxo) inhaler (n = 121) or terbutaline 500 micrograms qds via a reservoir powder inhaler device (n = 122). Apart from all bronchodilator treatment which was withdrawn at the start of the run-in period and replaced by inhaled salbutamol to be used as required for symptom relief, all concurrent medications were kept constant throughout the study. Salmeterol produced a significantly greater increase in mean morning peak expiratory flow (PEF) than terbutaline (difference in adjusted means after treatment = 28 l/min; 95% CI = 19-37 l/min; P < 0.001). Likewise, the increase in mean evening PEF was significantly greater following treatment with salmeterol than with terbutaline (difference in adjusted means = 9 l/min; 95% CI = 0-17 l/min; P = 0.045). Salmeterol was associated with a significant reduction in diurnal variation in PEF by comparison with terbutaline (difference in adjusted means = -18 l/min; 95% CI = -24, -12 l/min; P < 0.001). Significant improvements with salmeterol by comparison with terbutaline were also observed in daytime and night-time asthma scores, percentage of symptom-free days and nights, use of additional inhaled bronchodilator, and percentage of days and nights when no additional inhaled bronchodilator was needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Pilgrim's progress: the effect of salmeterol in older children with chronic severe asthma

Twenty-four children aged 12-17 years entered a randomized, double-blind placebo-controlled study investigating the use of salmeterol in chronic severe asthma. In addition to their usual medication, the children were given either placebo or 100 micrograms salmeterol b.d. by dry powder inhalation. Treatment was continued throughout one term at a residential school for asthma. Symptom scores, peak expiratory flow rates, spirometry and quality-of-life scores were compared between the two treatment groups. One child withdrew during the run-in period. Twelve pupils received placebo and 11 pupils received salmeterol. There were consistent improvements in favour of salmeterol, reaching statistical significance for morning and evening peak flow rates and spirometry when measured on four occasions during the study period. There were no medication-related adverse events recorded and no pulse rate changes. Salmeterol (100 micrograms b.d.) is well tolerated and efficacious in older children with chronic severe asthma.

Salmeterol. An appraisal of its quality-of-life benefits and potential pharmacoeconomic positioning in asthma

Salmeterol is a selective beta 2-receptor agonist with a long duration of action that permits twice daily administration. It is effective in the prophylaxis of asthma symptoms, including nocturnal and exercise-induced asthma, and it has shown clinical benefits in both adults and children. Because of its slow onset of action, salmeterol is not intended for relief of acute symptoms. The addition of salmeterol 50 micrograms twice daily to existing asthma therapy has a positive effect on patient quality of life in the short term (up to 3 months), as assessed by the Living With Asthma Questionnaire and Asthma Quality of Life Questionnaire. This improvement in well-being appears to be greater than that associated with salbutamol (albuterol). Furthermore, in patients with asthma symptoms despite inhaled corticosteroid therapy, a reduced dose of corticosteroid plus salmeterol produced a greater improvement in quality of life as assessed by a daily symptom diary (but not by the Living With Asthma Questionnaire), and was more clinically effective than a higher dose of corticosteroid alone. Evaluation of the effects of salmeterol on quality of life compared with other standard therapies, and extension of these results into the long term are required to consolidate these conclusions. Salmeterol 50 micrograms twice daily was associated with an estimated incremental cost of 736 pounds per symptom-free patient in the final week of 7.5 months' therapy, 648 pounds per patient with improved morning (am) peak expiratory flow rate (PEFR) and 1013 pounds per patient with improved evening (pm) PEFR compared with salbutamol (400 micrograms twice daily) in a cost-effectiveness analysis. However, these results should be tested by sensitivity analyses and compared with the incremental costs of other asthma interventions more applicable to recommended clinical practice. The cost effectiveness of salmeterol relative to other asthma therapies, and the effect of salmeterol on patient quality of life in the long term require further investigation. However, when added to existing asthma therapy, salmeterol improves patient quality of life in the short term (up to 3 months). It may also have some beneficial effects on patient well-being when used to provide a steroid-sparing effect.

The first 20 minutes after a single dose of inhaled salmeterol in asthmatic children

Very little is known as yet about the effect of salmeterol in pediatric asthma, so a trial was performed on children with mild asthma to compare salmeterol with salbutamol in terms of how quickly they took effect. The double-blind study involved 11 children (mean age 13.4 years) randomly assigned to inhale salmeterol 50 micrograms, salbutamol 200 micrograms, or a placebo three times on alternate days. Peak expiratory flow (PEF), heart rate, and blood pressure were measured before and 5, 10, 15, and 20 min after administering the medication. With salbutamol, PEF was higher at 5 and 10 min, subsequently dropping off at 15 and 20 min; with salmeterol, PEF was better at 10 and 20 min. Forced expiratory volume at 1 s (FEV1) measurements taken at the baseline and after 10 and 20 min revealed an important and consistent rise in values after salmeterol, whereas salbutamol was more effective after 10 min than after 20 min. No significant changes were recorded in heart rate or blood pressure after salbutamol; after salmeterol, there was a significant increase in heart rate after 5 min, but not at subsequent measurements. In conclusion, salmeterol begins to take effect already within 10 min of a single administration in asthmatic children, although the onset of its effect is slower than with salbutamol.

The effects of long-term treatment with salmeterol and salbutamol on the flow rate and composition of whole saliva in the rat

The effect of long-acting beta 2-adrenoceptor agonists on salivary glands and saliva secretion has not been studied before. Sprague-Dawley rats were given either the long-acting beta 2-agonist salmeterol, 1 mg/kg body wt per day or the short-acting agonist salbutamol, 5 mg/kg per day. Saline solution was used as control. After 18 days pilocarpine-stimulated saliva was collected, and after 21 days saliva was collected after stimulation with isoproterol and pilocarpine in combination. The saliva was analysed for total protein, amylase, hexosamine, sialic acid, sodium, potassium and calcium. At day 25 the salivary glands were extirpated and weighed. The weight of the parotid glands increased significantly after both salmeterol and salbutamol treatment, approx. 40%; the submandibular gland weights were not affected by either beta 2-agonist treatment. Pilocarpine-stimulated salivary flow rate was increased in the salbutamol, but not in the salmeterol, group. In the salmeterol group the concentration of sialic acid was increased and that of calcium was decreased. In saliva stimulated with pilocarpine and isoproterenol in combination, the concentrations of total protein, amylase and calcium were decreased after salmeterol. In the salbutamol group, total protein and potassium were decreased. The ratio sialic acid: total protein was increased at both saliva collections in both beta 2-agonist groups. It is concluded that rats treated chronically with the long-acting beta 2-adrenoceptor agonist salmeterol have an impaired secretion of salivary proteins and calcium and that the effect resembles that of salbutamol.

Comparison of Diskus inhaler, a new multidose powder inhaler, with Diskhaler inhaler for the delivery of salmeterol to asthmatic patients. Canadian Study Group

Administration of the long-acting beta 2-adrenoceptor agonist salmeterol from a new, easy-to-operate, multidose powder inhaler (Diskus) containing 60 sealed doses in a foil strip has been compared with administration from a Diskhaler inhaler in a multicenter, double-blind, double-dummy, parallel-group study. Asthmatic patients taking anti-inflammatory treatment, with baseline FEV1 > or = 60% and < or = 90% predicted were treated for 4 weeks with salmeterol 50 micrograms twice daily from either the Diskus or Diskhaler inhaler. The two treatments were equivalent (90% CLs for the difference in mean morning PEFR: -2.2, 8.7 L/min). The Diskus inhaler was rated easier to use and was preferred by more patients than the Diskhaler inhaler (73% vs. 15%).

Salmeterol in two different doses in the treatment of nocturnal bronchial asthma poorly controlled by other therapies

This study compared the efficacy of inhaled salmeterol (SM) 50 micrograms twice a day with SM 100 micrograms once a day (at night) and placebo in patients with poorly controlled nocturnal asthma despite treatment with corticosteroids, oral long-acting bronchodilators, or both. This was a two-center, double-blind, randomized, crossover study with three treatment periods, each of 3 weeks' duration. The first treatment period was preceded by two 1-week run-in periods, and the last treatment period was followed by a 2-week follow-up period. In the three treatment periods, patients received either SM 50 micrograms twice a day, SM 100 micrograms nightly, or placebo, in randomized order. Salbutamol metered-dose inhaler was given as relief medication. Of the 41 randomized patients, 38 were evaluable for more than one treatment period. Efficacy and safety were determined by daily record card data: morning and evening peak expiratory flow rates (PEFR), daytime and nighttime asthma symptom scores, and rescue salbutamol use. At clinic visits, FEV1 and FVC were measured, and the physicians' and the patients' respective assessments of the study mediation were noted. The study showed that the two doses, SM 50 micrograms twice a day and SM 100 micrograms nightly, were equally effective in controlling nocturnal asthma symptoms and were significantly better than placebo. SM was well tolerated, and no unexpected problems were revealed. The adverse events reported during this study were related either to the patient's underlying disease or to an intercurrent respiratory infection.

Salmeterol xinafoate in the treatment of mild to moderate asthma in primary care. UK Study Group

BACKGROUND

Clinical studies of inhaled salmeterol xinafoate have been conducted mainly in moderately to severely affected asthmatic subjects in hospital settings. This study was conducted to investigate the effectiveness of this drug in patients with milder asthma in primary care.

METHODS

A multicentre, double blind, randomised, parallel group comparison of salmeterol xinafoate in a dose of 50 micrograms twice daily with placebo, both administered from a four-place dry powder inhaler (Diskhaler), was performed over six weeks in United Kingdom general practices.

RESULTS

A total of 427 asthmatic patients aged 18 years or older were randomised to receive salmeterol or placebo in a 2:1 ratio. Of the total randomised population, 247 patients were previously on short acting bronchodilators alone whilst 180 patients were concurrently receiving up to 400 micrograms inhaled corticosteroid. Mean morning peak expiratory flow rose more in the salmeterol group than in the placebo group (treatment difference 17 l/min, 95% confidence interval 9 to 26 l/min) but there was a smaller, non-significant difference in mean evening peak expiratory flow. Improvements occurred in the salmeterol-treated group compared with placebo for wheeze, shortness of breath, undisturbed nights, and relief medication use, irrespective of concomitant inhaled corticosteroid use. In addition, improvement in activity restriction was seen in the salmeterol group compared with placebo in the subgroup receiving only bronchodilator.

CONCLUSIONS

Salmeterol is effective and well tolerated in the short term in mildly asthmatic adult patients irrespective of concomitant use of inhaled corticosteroid therapy.

The efficacy and tolerability of inhaled salmeterol and individually dose-titrated, sustained-release theophylline in patients with reversible airways disease

In a double-blind, double-dummy, cross-over, multicentre study, 141 patients with moderate reversible airways disease were randomized to receive either 50 micrograms salmeterol via a metered dose inhaler or individually dose-titrated oral theophylline, both twice daily for a 2-week period. Just over half (n = 77) the patients had received theophylline before, but 64 patients were new to theophylline therapy. Efficacy was based on lung function data and symptom scores. Salmeterol produced significantly higher increase in mean morning peak expiratory flow (PEF) of 161 min-1 (P < 0.001; 95% Confidence Interval (CI); 8-241 min-1) and mean evening PEF of 151 min-1 (p < 0.001; 95% CI; 7-221 min-1) compared with theophylline therapy. Further analysis of the data revealed that the increase in PEF with salmeterol compared with theophylline was highest in a sub-group of patients new to theophylline therapy. Patients on salmeterol had significantly less night-time awakenings than those on theophylline (P = 0.011) and significantly less daytime symptoms (P = 0.017). There was also a significant increase in the number of nights (P = 0.013) and days (P < 0.001) on salmeterol when no additional salbutamol was required compared with theophylline. Theophylline produced a higher incidence of adverse events compared with salmeterol. The results of this study show that inhaled salmeterol is more effective and better tolerated than individually dose-titrated oral theophylline over a 2-week study period in patients with moderate asthma.

Systemic effects of salbutamol and salmeterol in patients with asthma

BACKGROUND

Knowing the extent of the systemic effects of a new beta 2 agonist relative to an established drug is important for the prediction and interpretation of side effects. A recent study in which the effect of cumulative doses of salbutamol was compared with single doses of salmetreol suggested that, weight for weight, salmeterol may be up to 10 times more potent than salbutamol. This current study was designed to investigate further the dose equivalence of salmeterol and salbutamol.

METHODS

Twelve patients with mild asthma inhaled cumulative doses of placebo, salmeterol 25, 50, 100, and 200 micrograms, and salbutamol 100, 500, 1000, and 1000 micrograms on separate days at hourly intervals in a randomised double blind crossover study. Changes in forced expiratory volume in one second (FEV1), heart rate, plasma potassium concentration, systolic and diastolic blood pressure were measured. Dose equivalence was determined as the dose ratio of salmeterol to salbutamol for the 50% maximum response to salbutamol.

RESULTS

No important changes occurred in any measurements following placebo. Salmeterol and salbutamol caused a near maximum increase in FEV1 following the first dose so the dose equivalence for the airway effects could not be estimated. Heart rate increased and plasma potassium concentration and diastolic blood pressure decreased in a dose dependent manner following salmeterol and salbutamol, with median dose equivalences for salmeterol compared with salbutamol of 17.7, 7.8, and 7.6, respectively.

CONCLUSIONS

These results confirm that the systemic activity of salmeterol compared with salbutamol is higher than would be expected from in vitro data, particularly for heart rate. Whether this is because of the relatively high dose of salmeterol used or pharmacokinetic differences between the two drugs is uncertain.

Salmeterol: an inhaled beta 2-agonist with prolonged duration of action

Salmeterol (Serevent) is an inhaled beta 2-receptor agonist with more than twelve hours' effect duration compared with 4-6 hours for the more short-acting substances bitolterol, fenoterol, salbutamol, and terbutaline. Salmeterol has been studied in several large-scale double-blind multicenter studies with up to one year's duration. More than 6,000 asthmatics have been treated with salmeterol during these controlled studies. All studies show salmeterol to have a significantly better and well-maintained bronchodilating effect with better asthma control, fewer asthma exacerbations, and a decreased need for rescue albuterol inhalations used on demand compared to the treatments in the control groups (200-400 micrograms albuterol q.i.d., inhaled albuterol given only p.r.n., terbutaline given regularly, or individually titrated slow-release theophylline). Salmeterol should be given b.i.d. and in combination with inhaled corticosteroids. Salmeterol seems especially effective in patients with nocturnal symptoms, exercise induced asthma, and in patients sensitive to inhaled irritants such as cold air. The patients should always have short-acting inhaled beta 2-agonists available for break-through attacks. Inhaled salmeterol in combination with inhaled steroids seems to give the best maintenance asthma control available by inhalation today.