Inhaled short acting beta2-agonist use in asthma: regular vs as needed treatment

A novel GABAA receptor ligand MIDD0301 with limited blood-brain barrier penetration relaxes airway smooth muscle ex vivo and in vivo

Airway smooth muscle (ASM) cells express GABA A receptors (GABA_ARs), and previous reports have demonstrated that GABA_AR activators relax ASM. However, given the activity of GABA_ARs in central nervous system inhibitory neurotransmission, concern exists that these activators may lead to undesirable sedation. MIDD0301 is a novel imidazobenzodiazepine and positive allosteric modulator of the GABA_AR with limited brain distribution, thus eliminating the potential for sedation. Here, we demonstrate that MIDD0301 relaxes histamine-contracted guinea pig ( P < 0.05, n = 6-9) and human ( P < 0.05, n = 6-10) tracheal smooth muscle ex vivo in organ bath experiments, dilates mouse peripheral airways ex vivo in precision-cut lung-slice experiments ( P < 0.001, n = 16 airways from three mice), and alleviates bronchoconstriction in vivo in mice, as assessed by the forced-oscillation technique ( P < 0.05, n = 6 mice). Only trace concentrations of the compound were detected in the brains of mice after inhalation of nebulized 5 mM MIDD0301. Given its favorable pharmacokinetic properties and demonstrated ability to relax ASM in a number of clinically relevant experimental paradigms, MIDD0301 is a promising drug candidate for bronchoconstrictive diseases, such as asthma.

Serum Eosinophil Cationic Protein Is a Useful Marker for Assessing the Efficacy of Inhaled Corticosteroid Therapy in Children with Bronchial Asthma

Bronchial asthma (BA) is a chronic inflammatory disorder of airways for which the effective therapies include inhaled corticosteroids (ICS) and short-acting β2-adrenoreceptor agonist (SABA). Serum eosinophil cationic protein (ECP) has been reported to reflect the degree of airway inflammation. We, therefore, explored the implication of serum ECP in assessing the efficacy of ICS therapy in BA children. Our prospective randomized control study enrolled 126 BA children and 78 healthy children (the control group). The BA patients were randomly assigned as two groups; 59 children were treated with ICS, twice a day, for three months and 67 patients received SABA inhalation only if necessary. After the 3-month therapy, the serum levels of ECP, endothelin-1, and nitric oxide and the eosinophil percentage (EOS%) in induced sputum were significantly lower in the ICS group, compared with the SABA group, but were still higher than the control group (all P < 0.05). The forced expiratory volume (FEV1%pred) and forced vital capacity (FEV1/FVC) were improved to the levels of the control group after therapy. Pearson correlation analysis presented that higher serum ECP levels were associated with higher EOS% in serum and with lower pulmonary function indices (FEVl%pred and FEV1/FVC). Importantly, the ICS group exhibited higher quality of life scores and lower symptom scores compared with the SABA group (all P < 0.05). ROC results revealed the diagnostic efficiency of serum ECP levels on the efficacy of ICS. In conclusion, measuring serum ECP levels is helpful for assessing the efficacy of ICS therapy in BA children.

Asthma Review for Pharmacists Providing Asthma Education

Asthma is the most common pediatric illness affecting more than 6 million children in the United States. Children with asthma have more frequent office visits and hospitalizations compared with adults. Despite advances in therapies, asthma still has a significant effect on the health care system. Regardless of the setting, pharmacists are uniquely equipped with an intimate knowledge of medications. With this knowledge, they can provide education to patients at various points throughout the health care system, from hospitalization to office visits to point of pick up at the pharmacy. The goal of this article is to equip the pharmacist with the necessary knowledge to provide education to these patients in a variety of practice settings, including community pharmacies, ambulatory care settings, and during transitions in care.

Pharmacotherapy of critical asthma syndrome: current and emerging therapies

The critical asthma syndrome (CAS) encompasses the most severe, persistent, refractory asthma patients for the clinician to manage. Personalized pharmacotherapy is necessary to prevent the next acute severe asthma exacerbation, not just the control of symptoms. The 2007 National Asthma Education and Prevention Program Expert Panel 3 provides guidelines for the treatment of uncontrolled asthma. The patient's response to recommended pharmacotherapy is highly variable which risks poor asthma control leading to frequent exacerbations that can deteriorate into CAS. Controlling asthma symptoms and preventing acute exacerbations may be two separate clinical activities with their own unique demands. Clinicians must be prepared to use the entire spectrum of asthma medications available but must concurrently be aware of potential drug toxicities some of which can paradoxically worsen asthma control. Medications normally prescribed for COPD can potentially be useful in the CAS patient, particularly those with asthma-COPD overlap syndrome. Immunomodulation with drugs like omalizumab in IgE-mediated asthma syndromes is one important approach. New and emerging drugs address unique aspects of airway inflammation and biology but at a significant financial cost. The pharmacology and toxicities of the agents that may be used in the treatment of CAS to control asthma symptoms and prevent severe exacerbations are reviewed.

Continuous Inhalation of Ipratropium Bromide for Acute Asthma Refractory to β2-agonist Treatment

To present the case of a patient with persistent bronchospasm, refractory to treatment with β2-agonists, that resolved promptly with continuous inhalation of large dose (1000 mcg/hr) ipratropium bromide, and to discuss the possibility of tolerance to β2-agonists as the cause for his failure to respond to adrenergic medications. The patient had received multiple doses of albuterol, as well as subcutaneous terbutaline (0.3 mg), intravenous magnesium sulfate (1 g) and intravenous dexamethasone (10 mg) prior to his admission to the intensive care unit. He remained symptomatic despite systemic intravenous steroids, continuous intravenous terbutaline (up to 0.6 mcg/kg/min), and continuous nebulized albuterol (up to 20 mg/hr for 57 hr) followed by 49 hours of continuous levalbuterol (7 mg/hr). Due to the lack of response, all β2-agonists were discontinued at 106 hours post-admission, and he was started on large dose ipratropium bromide (1000 mcg/hr) by continuous nebulization. Clinical improvement was evident within 1 hour and complete resolution of his symptoms within 4 hours. Continuous inhalation of large dose ipratropium bromide may be an effective regimen for the treatment of patients hospitalized with acute asthma who are deemed to be nonresponsive and/or tolerant to β2-agonist therapy.

The asthma-chronic obstructive pulmonary disease overlap syndrome: pharmacotherapeutic considerations

Asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is a commonly encountered yet loosely defined clinical entity. ACOS accounts for approximately 15-25% of the obstructive airway diseases and patients experience worse outcomes compared with asthma or COPD alone. Patients with ACOS have the combined risk factors of smoking and atopy, are generally younger than patients with COPD and experience acute exacerbations with higher frequency and greater severity than lone COPD. Pharmacotherapeutic considerations require an integrated approach, first to identify the relevant clinical phenotype(s), then to determine the best available therapy. The authors discuss the array of existing and emerging classes of drugs that could benefit those with ACOS and share their therapeutic approach. A consensus international definition of ACOS is needed to design prospective, randomized clinical trials to evaluate specific drug interventions on important outcomes such as lung function, acute exacerbations, quality of life and mortality.

Childhood asthma: diagnosis and treatment

Many children suffer from recurrent coughing, wheezing and chest tightness. In preschool children one third of all children have these symptoms before the age of six, but only 40% of these wheezing preschoolers will continue to have asthma. In older school-aged children the majority of the children have asthma. Quality of life is affected by asthma control. Sleep disruption and exercised induced airflow limitation have a negative impact on participation in sports and social activities, and may influence family life. The goal of asthma therapy is to achieve asthma control, but only a limited number of patients are able to reach total control. This may be due to an incorrect diagnosis, co-morbidities or poor inhalation technique, but in the majority of cases non-adherence is the main reason for therapy failures. However, partnership with the parents and the child is important in order to set individually chosen goals of therapy and may be of help to improve control. Non-pharmacological measures aim at avoiding tobacco smoke, and when a child is sensitised, to avoid allergens. In pharmacological management international guidelines such as the GINA guideline and the British Guideline on the Management of Asthma are leading.

Albuterol enantiomer levels, lung function and QTc interval in patients with acute severe asthma and COPD in the emergency department

Background

This observational study was designed to investigate plasma levels of albuterol enantiomers among patients with acute severe asthma or COPD presenting to the emergency department, and the relationship with extra-pulmonary cardiac effects (QTc interval) and lung function. Recent reviews have raised concerns about the safety of using large doses of β₂-agonists, especially in patients with underlying cardiovascular comorbidity. It has been demonstrated that significant extrapulmonary effects can be observed in subjects given nebulised (R/S)-albuterol at a dose of as little as 6.5 mg.

Methods

Blood samples were collected and plasma/serum levels of (R)- and (S)-albuterol enantiomers were determined by LC-MS and LC-MS/MS assay. Extra-pulmonary effects measured at presentation included ECG measurements, serum potassium level and blood sugar level, which were collected from the hospital medical records.

Results

High plasma levels of both enantiomers were observed in some individuals, with median (range) concentrations of 8.2 (0.6-24.8) and 20.6 (0.5-57.3) ng/mL for (R)- and (S)- albuterol respectively among acute asthma subjects, and 2.1 (0.0-16.7) to 4.1 (0.0-36.1) ng/mL for (R)- and (S)- albuterol respectively among COPD subjects. Levels were not associated with an improvement in lung function or adverse cardiac effects (prolonged QTc interval).

Conclusions

High plasma concentrations of albuterol were observed in both asthma and COPD patients presenting to the emergency department. Extra-pulmonary cardiac adverse effects (prolonged QTC interval) were not associated with the plasma level of (R)- or (S)-albuterol when administered by inhaler in the emergency department setting. Long-term effect(s) of continuous high circulating albuterol enantiomer concentrations remain unknown, and further investigations are required.

Pharmacokinetic and pharmacodynamic comparison of hydrofluoroalkane and chlorofluorocarbon formulations of budesonide

AIMS

A hydrofluoroalkane formulation of budesonide pressurized metered-dose inhaler has been developed to replace the existing chlorofluorocarbon one. The aim of this study was to evaluate the pharmacokinetic and pharmacodynamic characteristics of both formulations.

METHODS

Systemic bioavailability and bioactivity of both hydrofluoroalkane and chlorofluorocarbon pressurized metered-dose inhaler formulations at 800 µg twice daily was determined during a randomized crossover systemic pharmacokinetic/pharmacodynamic study at steady state in healthy volunteers. Measurements included the following: plasma cortisol AUC(24h) [area under the concentration-time curve (0-24 h)], budesonide AUC(0-12h) and C(max) . Clinical efficacy was determined during a randomized crossover pharmacodynamic study in asthmatic patients receiving 200 µg followed by 800 µg budesonide via chlorofluorocarbon or hydrofluoroalkane pressurized metered-dose inhaler each for 4 weeks. Methacholine PC(20) (primary outcome), exhaled nitric oxide, spirometry, peak expiratory flow and symptoms were evaluated.

RESULTS

In the pharmacokinetic study, there were no differences in cortisol, AUC(0-12h) [area under the concentration-time curve (0-12 h)], T(max) (time to maximum concentration) or C(max) (peak serum concentration) between the hydrofluoroalkane and chlorofluorocarbon pressurized metered-dose inhaler. The ratio of budesonide hydrofluoroalkane vs. chlorofluorocarbon pressurized metered-dose inhaler for cortisol AUC(24h) was 1.02 (95% confidence interval 0.93-1.11) and budesonide AUC(0-12h) was 1.03 (90% confidence interval 0.9-1.18). In the asthma pharmacodynamic study, there was a significant dose response (P < 0.0001) for methacholine PC(20) (provocative concentration of methacholine needed to produce a 20% fall in FEV(1) ) with a relative potency ratio of 1.10 (95% confidence interval 0.49-2.66), and no difference at either dose. No significant differences between formulations were seen with the secondary outcome variables.

CONCLUSIONS

Hydrofluoroalkane and chlorofluorocarbon formulations of budesonide were therapeutically equivalent in terms of relative lung bioavailability, airway efficacy and systemic effects.

An integrative review of systematic reviews related to the management of breathlessness in respiratory illnesses

BACKGROUND

Breathlessness is a debilitating and distressing symptom in a wide variety of diseases and still a difficult symptom to manage. An integrative review of systematic reviews of non-pharmacological and pharmacological interventions for breathlessness in non-malignant disease was undertaken to identify the current state of clinical understanding of the management of breathlessness and highlight promising interventions that merit further investigation.

METHODS

Systematic reviews were identified via electronic databases between July 2007 and September 2009. Reviews were included within the study if they reported research on adult participants using either a measure of breathlessness or some other measure of respiratory symptoms.

RESULTS

In total 219 systematic reviews were identified and 153 included within the final review, of these 59 addressed non-pharmacological interventions and 94 addressed pharmacological interventions. The reviews covered in excess of 2000 trials. The majority of systematic reviews were conducted on interventions for asthma and COPD, and mainly focussed upon a small number of pharmacological interventions such as corticosteroids and bronchodilators, including beta-agonists. In contrast, other conditions involving breathlessness have received little or no attention and studies continue to focus upon pharmacological approaches. Moreover, although there are a number of non-pharmacological studies that have shown some promise, particularly for COPD, their conclusions are limited by a lack of good quality evidence from RCTs, small sample sizes and limited replication.

CONCLUSIONS

More research should focus in the future on the management of breathlessness in respiratory diseases other than asthma and COPD. In addition, pharmacological treatments do not completely manage breathlessness and have an added burden of side effects. It is therefore important to focus more research on promising non-pharmacological interventions.

Impact of bronchodilator therapy on exercise tolerance in COPD

Exercise tolerance is an important parameter in patients with COPD and a primary goal of treatment is to reduce dyspnea to facilitate physical activities and improve health-related quality of life. This review examines the link between expiratory flow limitation and dyspnea to explain the rationale for the use of bronchodilators and review the characteristics of different types of exercise tests, with specific focus on which tests are likely to show a response to bronchodilators. An earlier literature search of studies published up to 1999 assessed the effects of bronchodilatort therapy on dypsnea and exercise tolerance among patients with COPD. This current review examines the clinical evidence published since 1999. Thirty-one randomized studies of exercise tolerance associated with short- and long-acting beta(2)-agonists and anticholinergics were identified. Evidence for the efficacy of bronchodilators in enhancing exercise capacity is often contradictory and possibly depends on the exercise test and study methodology. However, further studies should confirm the benefit of long-acting bronchodilators in improving spontaneous everyday physical activities.

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

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

Pharmacogenetics of the beta 2-adrenergic receptor gene

Asthma is a complex genetic disease with multiple genetic and environmental determinants contributing to the observed variability in response to common antiasthma therapies. One focus of asthma pharmacogenetic research has been the beta2-adrenergic receptor gene (ADR beta 2) and its effect on individual responses to beta agonist therapy. Knowledge about the effects of ADR beta 2 variation on therapeutic responses is evolving and should not alter current Asthma Guideline approaches, which consist of the use of short-acting beta agonists (SABAs) for as-needed symptom-based therapy and the use of a regular long-acting beta agonist (LABA) in combination with inhaled corticosteroid therapy for those asthmatics whose symptoms are not controlled by inhaled corticosteroid alone. These approaches are based upon studies showing a consistent pharmacogenetic response to regular use of SABAs and less consistent findings in studies evaluating LABAs. The emerging pharmacogenetic studies are provocative and should lead to functional studies. Meanwhile, the conflicting data concerning LABAs may be caused by such factors as small sample sizes of study populations and differences in experimental design.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.

Beta2-agonists for asthma: the pediatric perspective

Inhaled beta-agonists are commonly prescribed for the treatment of wheezing disorders in infants and children. Despite this, there are concerns that these medications have potentially detrimental effects on lung health and symptoms. We will review the ontogeny of beta-agonist receptor and smooth muscle development from fetal life through infancy and childhood as well as the evidence supporting the clinical utility of beta-agonists in wheezing infants and asthmatic children. Finally, the potential detrimental effects of long- and short-acting beta-agonists in infants and children are discussed.

Overcoming gaps in the management of asthma in older patients: new insights

Asthma is under-recognised and undertreated in older populations. This is not surprising, given that one-third of older people experience significant breathlessness. The differential diagnosis commonly includes asthma, chronic obstructive pulmonary disease (COPD), heart failure, malignancy, aspiration and infections. Because symptoms and signs of several cardiorespiratory diseases are nonspecific in older people and diseases commonly co-exist, investigations are important. A simple strategy for the investigation of breathlessness in older people should include a full blood count, chest radiograph, ECG, peak flow diary and/or spirometry with reversibility as a minimum. If there are major abnormalities on the ECG, an echocardiogram should also be performed. Diurnal variability in peak flow readings >or=20% or >or=15% reversibility in forced expiratory volume in 1 second, spontaneously or with treatment, support a diagnosis of asthma. Distinguishing asthma from COPD is important to allow appropriate management of disease based on aetiology, accurate prediction of treatment response, correct prognosis and appropriate management of the chest condition and co-morbidities. The two conditions are usually readily differentiated by clinical features, particularly age at onset, variability of symptoms and nocturnal symptoms in asthma, supported by the results of reversibility testing. Full lung function tests may not necessarily help in differentiating the two entities, although gas transfer factor is characteristically reduced in COPD and usually normal or high in asthma. Methacholine challenge tests previously mainly used in research are now also used widely and safely to confirm asthma in clinical settings. Interest in exhaled nitric oxide as a biomarker of airways inflammation is increasing as a noninvasive tool in the diagnosis and monitoring of asthma. Regular inhaled corticosteroids (ICS) are the mainstay of treatment of asthma. Even in mild disease in older adults, regular preventive treatment should be considered, given the poor perception of bronchoconstriction by older asthmatic patients. If symptoms persist despite ICS, addition of long-acting beta(2)-adrenoceptor agonists (LABA) should be considered. Addition of LABA to ICS improves asthma control and allows reduction in ICS dose. However, older people have been grossly under-represented in trials of LABA, many trials having excluded those >or=65 years of age. On meta-analysis, beta(2)-adrenoceptor agonists (both short acting and long acting) are associated with increased cardiovascular mortality and morbidity in asthma and COPD. While the evidence for excess cardiovascular mortality is stronger for short-acting beta(2)-adrenoceptor agonists, it would be prudent to exercise particular care in using beta(2)-adrenoceptor agonists (long acting and short acting) in those at risk of adverse cardiovascular outcomes, including older people. Regular review of cardiovascular status (and monitoring of serum potassium concentration) in patients taking beta(2)-adrenoceptor agonists is crucial. The response to LABA should be carefully monitored and alternative 'add-on' therapy such as leukotriene receptor antagonists (LRA) should be considered. LRA have fewer adverse effects and in individual cases may be more effective and appropriate than LABA. Long-term trials evaluating beta(2)-adrenoceptor agonists and other bronchodilator strategies are needed particularly in the elderly and in patients with cardiovascular co-morbidities. There is no evidence that addition of anticholinergics improves control of asthma further, although the role of long-acting anticholinergics in the prevention of disease progression is currently being researched. Older patients need to be taught good inhaler technique to improve delivery of medications to lungs, minimise adverse effects and reduce the need for oral corticosteroids. Nurse-led education programmes that include a written asthma self-management plan have the potential to improve outcomes.

Beclomethasone dipropionate attenuates airways hyperresponsiveness to neurokinin A and histamine in asthma

BACKGROUND

Inhaled corticosteroids (ICS) are the most effective anti-inflammatory agents available for the treatment of asthma but they produce only modest effects on airway inflammation and non-specific bronchial hyperresponsiveness (BHR). However, little is known about the possibility that treatment with ICS might cause additional protection on BHR to inhaled tachykinins such as neurokinin A (NKA).

OBJECTIVE

Therefore, we compared the effects of beclomethasone dipropionate (BDP) on the degree of BHR to inhaled histamine and NKA in a double-blind, controlled, cross-over study of asthmatic patients.

METHODS

Patients attended the laboratory before and after each 6 weeks treatment period to undertake concentration-response studies with histamine and NKA. Bronchial responsiveness to both funs was expressed as the provocative concentration producing a 20% decrease in FEV(1) from baseline (PC(20)).

RESULTS

BDP therapy attenuated the constrictor response to both agonists to a similar degree, their geometric mean (range) PC(20) values increasing from 0.47 (0.21-1.41) mg/ml to 2.43 (0.51-4.50) mg/ml (P<0.01, post-salb vs. post-BDP treatment) and from 101.7 (27.3-356.1) microg/ml to 666.7 (151.5-1,000) microg/ml (P<0.01, post-salb vs. post-BDP treatment) for histamine and NKA, respectively.

CONCLUSION

Airway responsiveness to histamine and NKA is reduced by BDP to the same extent. As a result of these findings, provocation with NKA is unlikely to provide additional useful information in the assessment of airway inflammation in asthma.

Repeat prescribing: scale, problems and quality management in ambulatory care patients

The reported scale of repeat prescriptions ranges from 29% to 75% of all items prescribed, depending on the definition of repeat prescribing and other variables. It is likely that a substantial part of repeat prescribing by general practitioners (GPs) occurs without direct doctor-patient contact. While this reduces the workload for the GP and is convenient for the patient, it does not provide the adequate control that is needed to ensure that every repeat prescription is still appropriate, effective and well tolerated, and that it is still being viewed upon and taken by the patient as intended. Infrequent therapy reviews may lead to failure to prevent, identify and solve drug-related problems and drug wastage, and may, thereby, have a negative impact on the effectiveness, safety or cost of the medications prescribed. Studies evaluating the repeat prescribing process have shown that GPs and medical practices vary widely in their degree of administrative and clinical control of repeat prescriptions. Contrary to the opinion that GPs cannot change prescribing behaviour when the prescription is initiated by a medical specialist, GPs have their own responsibility for controlling the repeats of such prescriptions. Intervention studies suggest that a medication review by a pharmacist can help to reduce drug-related problems with repeat prescriptions, and the effectiveness of the intervention may be increased by combining the medication review with a consultation of the patient's medical records and a patient interview. In several studies, such an intervention was relatively inexpensive and, therefore, feasible. However, these conclusions should be viewed with appropriate caution because a number of caveats pertain. There is still no evidence that these types of intervention improve health-related quality of life or reduce healthcare cost, and so far only a few trials have produced any evidence of clinical improvement. As implicit and explicit screening criteria have their own benefits and limitations, a combined application may offer a more thorough assessment but may also be more complex and time consuming. Further studies on the development and evaluation of repeat prescription management models are needed, preferably focussing on improving clinical, humanistic and economic outcomes. New studies should investigate the effects of: different types of interventions; different organisational models; different target populations; and selecting and training different types of healthcare professionals. Future studies should also assess whether results are sustained, the optimal time interval between reviews of repeat prescriptions, and the possibilities offered by new computerised support technologies.

Therapeutic responses in asthma and COPD. Bronchodilators

The presence of acute reversibility to bronchodilators does not distinguish asthma from COPD. Patients with either condition can benefit from bronchodilators, and should be given a trial to assess their response. Some respond with a change in lung volume with less hyperinflation; others improve their forced inspiratory flow and become much more comfortable. The combination of long-acting beta-agonists (LABAs) and inhaled steroids is useful in both conditions. While anticholinergics seem to yield the best results in COPD, some patients with asthma benefit from their use. Tiotropium may be the most effective agent as monotherapy in COPD, but the combination of an inhaled steroid and a LABA may produce similar results in improving lung function. Long-acting bronchodilators are effective agents as monotherapy in COPD, but in asthma should be combined with a controller medication. Short-acting beta-agonists should be used intermittently in asthma, but may be used regularly or combined with an anticholinergic in COPD. The roles of stereoisomers, leukotriene receptor antagonists, and type 4 phosphodiesterase inhibitors in asthma and COPD remain uncertain at this time.

Management of asthma in adults: current therapy and future directions

Asthma is increasing in prevalence worldwide and results in significant use of healthcare resources. Although most patients with asthma can be adequately treated with inhaled corticosteroids, an important number of patients require additional therapy and an increasing number of options are available. A further minority of patients develop severe persistent asthma which remains difficult to manage despite current pharmacological therapies. This review discusses the various treatment options currently available for each stage of asthma severity, highlights some of the limitations of current management, and outlines directions which may improve the management of asthma in the future.