A comparison of terbutaline inhaled by Turbuhaler and by a chlorofluorocarbon (CFC) inhaler in children with exercise-induced asthma

Repurposing drugs as inhaled therapies in asthma

For the first 40 years of the 20th century treatment for asthma occurred in response to an asthma attack. The treatments were given by injection or orally and included the adrenergic agonists adrenalin/epinephrine and ephedrine and a phosphodiesterase inhibitor theophylline. Epinephrine became available as an aerosol in 1930. After 1945, isoprenaline, a non-selective beta agonist, became available for oral use but it was most widely used by inhalation. Isoprenaline was short-acting with unwanted cardiac effects. More selective beta agonists, with a longer duration of action and fewer side-effects became available, including orciprenaline in 1967, salbutamol in 1969 and terbutaline in 1970. The inhaled steroid beclomethasone was available by 1972 and budesonide by 1982. Spirometry alone and in response to exercise was used to assess efficacy and duration of action of these drugs for the acute benefits of beta₂ agonists and the chronic benefits of corticosteroids. Early studies comparing oral and aerosol beta₂ agonists found equivalence in bronchodilator effect but the aerosol treatment was superior in preventing exercise-induced bronchoconstriction. Inhaled drugs are now widely used including the long-acting beta₂ agonists, salmeterol and formoterol, and the corticosteroids, fluticasone, ciclesonide, mometasone and triamcinolone, that act locally and have low systemic bio-availability. Repurposing drugs as inhaled therapies permitted direct delivery of low doses of drug to the site of action reducing the incidence of unwanted side-effects and permitting the prophylactic treatment of asthma.

Beta₂-agonists for exercise-induced asthma

BACKGROUND

It is well known that physical exercise can trigger asthma symptoms and can induce bronchial obstruction in people without clinical asthma. International guidelines on asthma management recommend the use of beta2-agonists at any stage of the disease. At present, however, no consensus has been reached about the efficacy and safety of beta2-agonists in the pretreatment of exercise-induced asthma and exercise-induced bronchoconstriction. For the purpose of the present review, both of these conditions are referred to by the acronymous EIA, independently from the presence of an underlying chronic clinical disease.

OBJECTIVES

To assess the effects of inhaled short- and long-acting beta2-agonists, compared with placebo, in the pretreatment of children and adults with exercise-induced asthma (or exercise-induced bronchoconstriction).

SEARCH METHODS

Trials were identified by electronic searching of the Cochrane Airways Group Specialised Register of Trials and by handsearching of respiratory journals and meetings. Searches are current as of August 2013.

SELECTION CRITERIA

We included randomised, double-blind, placebo-controlled trials of any study design, published in full text, that assessed the effects of inhaled beta2-agonists on EIA in adults and children. We excluded studies that did not clearly state diagnostic criteria for EIA.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by The Cochrane Collaboration.

MAIN RESULTS

We included 53 trials consisting of 1139 participants. Forty-eight studies used a cross-over design, and five were performed in accordance with a parallel-group design. Forty-five studies addressed the effect of a single beta2-agonist administration, and eight focused on long-term treatment. We addressed these two different intervention regimens as different comparisons.Among primary outcomes for short-term administration, data on maximum fall in forced expiratory volume in 1 second (FEV1) showed a significant protective effect for both short-acting beta-agonists (SABA) and long-acting beta-agonists (LABA) compared with placebo, with a mean difference of -17.67% (95% confidence interval (CI) -19.51% to -15.84%, P = 0.00001, 799 participants from 72 studies). The subgroup analysis of studies performed in adults compared with those performed in children showed high heterogeneity confined to children, despite the comparable mean bronchoprotective effect.Secondary outcomes on other pulmonary function parameters confirmed a more positive and protective effect of beta2-agonists on EIA compared with placebo. Occurrence of side effects was not significantly different between beta2-agonists and placebo.Overall evaluation of the included long-term studies suggests a beta2-agonist bronchoprotective effect for the first dose of treatment. However, long-term use of both SABA and LABA induced the onset of tolerance and decreased the duration of drug effect, even after a short treatment period.

AUTHORS' CONCLUSIONS

Evidence of low to moderate quality shows that beta2-agonists, both SABA and LABA, when administered in a single dose, are effective and safe in preventing EIA.Long-term regular administration of inhaled beta2-agonists induces tolerance and lacks sufficient safety data. This finding appears to be of particular clinical relevance in view of the potential for prolonged regular use of beta2-agonists as monotherapy in the pretreatment of EIA, despite the warnings of drug agencies (FDA, EMA) regarding LABA.

Pharmacotherapy for exercise-induced asthma: allowing normal levels of activity and sport

Exercise-induced bronchoconstriction (EIB) is experienced by the majority of an estimated 300 million individuals who have asthma, a condition that affects all ages and is increasing globally. Respiratory water loss with dehydration of the airways causing mediator release and airway narrowing is considered the cause of EIB, the severity of which will be increased if the inhaled air is cold or polluted. Adequate control of asthma is essential to minimize or prevent EIB and permit normal levels of physical activity and sport. This is important because exercise is a necessary component of daily living, assists in obtaining and maintaining a healthy body and has been demonstrated to benefit asthmatics. Inhaled glucocorticosteroids and inhaled β(2)-adrenoceptor agonists (IβA) are the pharmacological agents of choice to manage asthma and minimize EIB, assisted when necessary, by other drugs including leukotriene receptor antagonists and chromones. Tolerance from daily use of IβA is of concern and more flexible drug therapy needs to be considered. Optimal use of inhalers to deliver drugs effectively requires closer attention. Pharmacogenetics may hold the key to future drug therapy.

Paediatric pulmonary drug delivery: considerations in asthma treatment

Aerosol therapy, the preferred route of administration for glucocorticosteroids and short-acting beta(2)-adrenergic agonists in the treatment of paediatric asthma, may be given via nebulisers, metered-dose inhalers and dry powder inhalers. For glucocorticosteroids, therapy with aerosolised medication results in higher concentrations of drug at the target organ with minimal systemic side effects compared with oral treatments. The dose of drug that reaches the airways in children with asthma is dependent on both the delivery device and patient-related factors. Factors that affect aerosol drug delivery are reviewed briefly. Advantages and disadvantages of each device and device-specific factors that influence patient preferences are examined. Although age-based device recommendations have been made, the optimal choice for drug delivery is the one that the patient or caregiver prefers to use, can use correctly and is most likely to use consistently.

Device Selection and Outcomes of Aerosol Therapy: Evidence-Based Guidelines

BACKGROUND

The proliferation of inhaler devices has resulted in a confusing number of choices for clinicians who are selecting a delivery device for aerosol therapy. There are advantages and disadvantages associated with each device category. Evidence-based guidelines for the selection of the appropriate aerosol delivery device in specific clinical settings are needed.

AIM

(1) To compare the efficacy and adverse effects of treatment using nebulizers vs pressurized metered-dose inhalers (MDIs) with or without a spacer/holding chamber vs dry powder inhalers (DPIs) as delivery systems for beta-agonists, anticholinergic agents, and corticosteroids for several commonly encountered clinical settings and patient populations, and (2) to provide recommendations to clinicians to aid them in selecting a particular aerosol delivery device for their patients.

METHODS

A systematic review of pertinent randomized, controlled clinical trials (RCTs) was undertaken using MEDLINE, EmBase, and the Cochrane Library databases. A broad search strategy was chosen, combining terms related to aerosol devices or drugs with the diseases of interest in various patient groups and clinical settings. Only RCTs in which the same drug was administered with different devices were included. RCTs (394 trials) assessing inhaled corticosteroid, beta2-agonist, and anticholinergic agents delivered by an MDI, an MDI with a spacer/holding chamber, a nebulizer, or a DPI were identified for the years 1982 to 2001. A total of 254 outcomes were tabulated. Of the 131 studies that met the eligibility criteria, only 59 (primarily those that tested beta2-agonists) proved to have useable data.

RESULTS

None of the pooled metaanalyses showed a significant difference between devices in any efficacy outcome in any patient group for each of the clinical settings that was investigated. The adverse effects that were reported were minimal and were related to the increased drug dose that was delivered. Each of the delivery devices provided similar outcomes in patients using the correct technique for inhalation.

CONCLUSIONS

Devices used for the delivery of bronchodilators and steroids can be equally efficacious. When selecting an aerosol delivery device for patients with asthma and COPD, the following should be considered: device/drug availability; clinical setting; patient age and the ability to use the selected device correctly; device use with multiple medications; cost and reimbursement; drug administration time; convenience in both outpatient and inpatient settings; and physician and patient preference.

Clinical efficacy of inhaler devices containing beta(2)-agonist bronchodilators in the treatment of asthma: cochrane systematic review and meta-analysis of more than 100 randomized, controlled trials

BACKGROUND

A number of different inhaler devices are available to deliver beta(2)-adrenoceptor agonist (beta(2)-agonist) bronchodilators in asthma. These include hydrofluoroalkane or chlorofluorocarbon (CFC)-free propelled pressurized metered-dose inhalers (pMDIs), many dry powder inhalers and breath-actuated inhalers.

OBJECTIVE

To determine the clinical efficacy of all available hand-held inhaler devices compared with the standard CFC-containing pMDI for the delivery of short-acting beta(2)-agonist bronchodilators in nonacute asthma in both children and adults.

METHODOLOGY

A systematic review and meta-analysis was carried out of all available randomized, controlled trials (RCTs) using the standard pMDI compared with any other hand-held inhaler device, delivering short-acting beta(2)-agonist bronchodilators in patients with stable asthma.

RESULTS

One hundred and eighteen RCTs were included in this review. No clinical differences were found between the standard CFC-containing pMDI and 12 other hand-held inhaler devices for most outcome measures. We found no evidence of clinical differences between studies using either a 1 : 1 (pMDI: another inhaler) or a 2 : 1 dosing ratio.

CONCLUSIONS

In patients with stable asthma, short-acting beta(2)-agonist bronchodilators in standard CFC-pMDIs are as effective as any other hand-held inhaler device; therefore the cheapest available device that the patient is able to use should always be considered. Pharmaceutical companies should in future submit to regulatory authorities clinical outcome data (as opposed to in vitro data) in support of any dosing schedules greater than 1 : 1 when compared with the standard pMDI. Clinical effectiveness studies that use an intention-to-treat analysis and report more patient-centered outcomes are required.

The influence of inhaler selection on efficacy of asthma therapies

Many different devices are available to aid inhalational drug delivery. Although each device is claimed to have advantages over its rivals, the evidence to support greater efficacy of a particular device is scanty. Most comparative studies are underpowered or flawed in their design. They may use inappropriate end-points, or involve healthy subjects, whose response may be very different from the patient with acute severe asthma. The dosage of drug used in a trial may be at the shallow part of the dose-response curve, masking differences in devices. Only in a few cases have clinical trials detected a significant difference between devices, and trials have rarely taken patient preference into account. The most efficacious device in practice is likely to be the one that the patient will use regularly and in accordance with a health care workers' recommendations.

Pressurised metered-dose inhalers (MDIs) versus dry powder inhalers devices (DPIs) to rapid-acting inhaled b2-agonists for asthma in children

OBJECTIVE

To compare the clinical effectiveness of pressurized metered-dose inhalers (MDIs) with that of dry powder inhalers (DPIs) in delivering short-acting b2-agonists in children with asthma.

METHODS

Searches were performed in Medline (1997-March 2002), the Cochrane Library Database and the Embase reference lists of review articles and clinical trials. In addition, the international headquarters of b2-agonist manufacturers were contacted. We performed a review of randomized controlled trials.

RESULTS

Ten randomized controlled trials were included. No differences in clinical effectiveness were found between MDIs and PDIs. Two studies reported that fewer adverse events occurred when the Turbuhaler was used. Two long-term studies in children found that children preferred the MDI to the Rotohaler.

CONCLUSIONS

1) In stable asthma, short-acting b2 bronchodilators in standard MDIs are as effective as dry powder inhalers. 2) Pooling of results was limited by the small number of studies and therefore no overall conclusions could be drawn. 3) From the limited data available, we found little or no evidence for an additional clinical benefit of DPI devices over standard MDIs in children with asthma.

Balancing Safety and Efficacy in Pediatric Asthma Management

In the treatment of childhood asthma, balancing safety and efficacy is key to achieving optimal therapeutic benefit. Inhaled corticosteroids (ICS), because of their efficacy, remain a cornerstone in managing persistent pediatric asthma, but also are associated with significant adverse effects, including growth suppression. Consequently, careful attention must be given to balancing their safety and efficacy, which should include an understanding of airway patency and systemic absorption (dose, disease severity, propellant and lipophilicity of inhalant), bioavailability (inhalation technique, propellant, delivery devices, and hepatic first-pass metabolism), techniques for using minimum effective doses (dosing time, add-on therapy), and reduction of other exacerbating conditions (allergens, influenza, upper-respiratory diseases). The growth-suppressive effects of ICS may be most evident in children with: 1) mild asthma because the relatively high airway patency may facilitate increased levels of deposition and steroid absorption in more distal airways, and 2) evening dosing that may reduce nocturnal growth hormone activity. A step-down approach targeting a minimum effective dose and once-daily morning dosing is suggested for achieving the most acceptable safety/efficacy balance with ICS. The achievement of regular, safe, and correct ICS use requires significant knowledge and time for both caregiver and patient. Chromones, methylxanthines, long-acting β-agonists, and leukotriene receptor antagonists are currently available alternatives to ICS for the control of persistent childhood asthma. Chromones are safe but, like methylxanthines, are difficult to use and frequently result in compromised effectiveness. Long-acting β-agonists are not recommended as monotherapy for persistent asthma. Several factors that support leukotriene receptor antagonists as a therapeutic option for mild-to-moderate persistent pediatric asthma include established efficacy, good safety profiles, and simple, oral dosing. Physicians must evaluate and compare the balance of safety and efficacy for each agent to determine the appropriate asthma therapy for individual patients.

Pressurised metered dose inhalers versus all other hand-held inhaler devices to deliver beta-2 agonist bronchodilators for non-acute asthma

BACKGROUND

A number of different inhaler devices are available to deliver beta2-agonist bronchodilators in asthma. These include hydrofluoroalkane (HFA) or chlorofluorocarbon (CFC)-free propelled pressurised metered dose inhalers (pMDIs) and dry powder devices.

OBJECTIVES

To determine the clinical effectiveness of pMDI compared with any other available handheld inhaler device for the delivery of short-acting beta-2 agonist bronchodilators in non-acute asthma in children and adults.

SEARCH STRATEGY

The Cochrane Collaboration Clinical Trials register was searched for studies as well as separate additional searches carried out on MEDLINE, EMBASE, CINAHL and also on the Current Contents Index as well as the Science Citation Index. In addition, 17 individual online respiratory journals and 12 electronically available clinical trial databases were also searched. The UK pharmaceutical companies who manufacture inhaled asthma medication were contacted in order to obtain details of any published or unpublished studies.

SELECTION CRITERIA

- The full texts of all potentially relevant articles were reviewed independently by two reviewers.

DATA COLLECTION AND ANALYSIS

Fixed and random effect models were used. Dichotomous outcomes were assessed using Odds Ratios or Relative Risks (RR) with 95% Confidence Intervals (95%CI).

MAIN RESULTS

Eighty-four randomised controlled trials were included in this review, but few could be combined to assess a specific outcome for a given delivery device comparison. Only two studies required demonstration of adequate pMDI technique as an entry requirement. There were no difference between a standard CFC containing pMDI and any other device for most outcomes. Regular use of HFA-pMDI containing salbutamol reduced the requirement for short courses of oral corticosteroids (3 trials, 519 patients: RR 0.67; 95% CI 0.49, 0.91); however the total number of exacerbations were unchanged (3 trials, 1271 patients: RR 1.0; 95% CI 0.75, 1.33).

REVIEWER'S CONCLUSIONS

In patients with stable asthma, short-acting beta-2 bronchodilators in standard CFC-pMDI's are as effective as any other devices. The effect of HFA-pMDI on requirement for oral corticosteroid courses to treat acute exacerbations should be confirmed. Effectiveness studies that use an intention-to-treat analysis are required.

Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering beta (2 )agonists bronchodilators in asthma

OBJECTIVES

To determine the clinical effectiveness of pressurised metered dose inhalers compared with other hand held inhaler devices for delivering short acting beta(2) agonists in stable asthma.

DESIGN

Systematic review of randomised controlled trials.

DATA SOURCES

Cochrane Airways Group specialised trials database (which includes hand searching of 20 relevant journals), Medline, Embase, Cochrane controlled clinical trials register, pharmaceutical companies, and bibliographies of included trials.

TRIALS

All trials in children or adults with stable asthma that compared the pressurised metered dose inhaler (with or without a spacer device) against any other hand held inhaler device containing the same beta(2) agonist.

RESULTS

84 randomised controlled trials were included. No differences were found between the pressurised metered dose inhaler and any other hand held inhaler device for lung function, blood pressure, symptoms, bronchial hyperreactivity, systemic bioavailability, inhaled steroid requirement, serum potassium concentration, and use of additional relief bronchodilators. In adults, pulse rate was lower in those using the pressurised metered dose inhaler compared with those using Turbohaler (standardised mean difference 0.44, 95% confidence interval 0.05 to 0.84); patients preferred the pressurised metered dose inhaler to the Rotahaler (relative risk 0.53, 95% confidence interval 0.36 to 0.78); hydrofluoroalkane pressurised metered dose inhalers reduced the requirement for rescue short course oral steroids (relative risk 0.67, 0.49 to 0.91).

CONCLUSIONS

No evidence was found to show that alternative inhaler devices are more effective than standard pressurised metered dose inhalers for delivering acting beta(2 )agonist bronchodilators in asthma. Pressurised metered dose inhalers remain the most cost effective delivery devices.

Latest advances in the development of dry powder inhalers

The current market for dry powder inhalers (DPIs) has over 20 devices in present use and at least another 30 under development. Clinicians recognize that DPIs are a suitable alternative to pressurized metered dose inhalers (pMDIs) for some patients but the relative performance of devices is often unclear. The problem is compounded by the need to reformulate pMDIs with new propellants, introducing further products to the market with associated variations in performance. This article reviews the DPIs currently available, the driving forces governing new designs, and the claimed advantages of DPIs in the development pipeline.

Review of therapeutically equivalent alternatives to short acting beta(2) adrenoceptor agonists delivered via chlorofluorocarbon-containing inhalers

BACKGROUND

To study the transition from metered dose inhalers using chlorofluorocarbons as propellants (CFC-MDIs) to non-CFC containing devices, a systematic review was conducted of clinical trials which compared the delivery of salbutamol and terbutaline via CFC-MDIs and non-CFC devices.

METHODS

Papers were selected by searching electronic databases (Medline, Cochrane, and BIDS) and further information and studies were sought from pharmaceutical companies. The studies were assessed for their methodological quality.

RESULTS

Fifty three relevant trials were identified. Most were scientifically flawed in terms of study design, comparison of inappropriate doses, and insufficient power for the determination of therapeutic equivalence. Differences between inhaler devices were categorised according to efficacy and potency. Most trials claimed to show therapeutic equivalence, usually for the same doses from the different devices. Two commercially available salbutamol metered dose inhalers using a novel hydrofluorocarbon HFC-134a as propellant were equally as potent and efficacious as conventional CFC-MDIs, as were the Rotahaler and Clickhaler dry powder inhalers (DPIs). Evidence suggests that a dose of 200 microg salbutamol via CFC-MDI may be substituted with 200 microg and 400 microg of salbutamol via Accuhaler and Diskhaler DPIs, respectively. Terbutaline delivered via a Turbohaler DPI is equally as potent and efficacious as terbutaline delivered via a conventional CFC-MDI.

CONCLUSIONS

When substituting non-CFC containing inhalers for CFC-MDIs, attention must be given to differences in inhaler characteristics which may result in variations in pulmonary function.

Exercise-induced asthma in children: a comparative study of free and treadmill running

BACKGROUND

Exercise is one of the most common precipitating factors of acute asthmatic crises in childhood. Although it has been described as more frequent among children, this is probably due to their more abundant physical activity. Nevertheless, it also occurs at other ages.

OBJECTIVE

The aim of this study is to assess possible differences in postexercise spirometry after treadmill and free running provocation tests.

METHODS

We compared the results obtained in a treadmill test performed by 30 asthmatic children and 30 healthy children with the results obtained with these same children in a free running test, keeping similar environmental conditions (temperature and humidity), exercise intensity (assessed by heart rate), and airway status at the time of the test.

RESULTS

Seventy-three percent of the patients had positive treadmill tests and 63.3% had positive free running tests. For the spirometric parameters studied, there were no significant differences in the percent decrease in postexercise performance after either of the provocation tests. For FEV1, which is the most sensitive diagnostic parameter, the sensitivity was 53.3% in treadmill running and 56.7% in free running, with a specificity of 100% in both tests.

CONCLUSIONS

If environmental conditions, exercise intensity, and airway status are controlled at the time of the test, treadmill and free running can be used indistinctly as asthma-inducing exercises.

Influence of inspiratory capacity on bronchodilatation via Turbuhaler or pressurized metered-dose inhaler in asthmatic children: a comparison

This study was designed to compare the bronchodilatatory effect of terbutaline inhaled through Turbuhaler (TH) or pressurized metered-dose inhaler (pMDI) in young asthmatics, and to assess the possible relationship between patients' inspiratory capacity and bronchodilatation for both devices. One hundred and eighteen asthmatics (aged 4 10/12-20 6/12 years) with bronchial obstruction (mean Vmax 50%: 59.5% pred, SD 17.8% pred) were allocated at random to two groups of 59 patients to inhale 0.5 mg terbutaline either by TH or by pMDI (and placebo by dummy of the other device). In- and expiratory spirometry and bodyplethysmography were conducted before and 10 min after inhalation. Bronchodilatation was effective [change in airways resistance (delta RAW) -50%, change in forced expiratory volume in 1 s (delta FEV1)+15%, delta Vmax 50% or 25% + 25% of baseline] in 41 of 59 patients with pMDI (69.5%) and 33 of 59 patients with TH (55.9%). The effect on Vmax 50% was significantly better with pMDI than with TH. Turbuhaler users with higher inspiratory flow [forced inspiratory volume in 1 s (FIV1), forced inspiratory flow at 50% vital capacity (FIF50)] reached better bronchodilatation, while bronchodilatatory effect was not correlated with inspiratory performance in MDI users. Peak inspiratory flow (PIF) did not correlate well with bronchodilatation by TH. When using TH for bronchodilatation, the effectiveness of terbutaline depends upon the degree of inspiratory capacity. This can lead to impaired bronchodilatatory effect in subgroups of obstructive young asthmatics with low inspiratory flow. In contrast, when using a pMDI, inspiratory capacity does not seem to influence the effectiveness of terbutaline.