Effect of controlled-release salbutamol in predominantly non-reversible chronic airflow obstruction

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.

Six-minute walking versus shuttle walking: responsiveness to bronchodilation in chronic obstructive pulmonary disease

BACKGROUND

The responsiveness of the endurance shuttle walk to functional changes following bronchodilation has recently been reported. The current literature suggests that the 6 min walking test (6MWT) is less responsive to bronchodilation than the endurance shuttle walk.

AIM

To compare bronchodilator-induced changes in exercise performance with the 6MWT and the endurance shuttle walk.

METHODS

In a randomised, double-blind, placebo-controlled, crossover trial, 14 patients with chronic obstructive pulmonary disease (forced expiratory volume in 1 s (FEV(1)) 50 (8)% predicted) completed two 6MWTs and two endurance shuttle walks, each preceded by nebulised placebo or 500 microg ipratropium bromide. Cardiorespiratory parameters were monitored during each walking test with a portable telemetric gas analyser. Quadriceps twitch force was measured by magnetic stimulation of the femoral nerve before and after each walking test.

RESULTS

The 6 min walking distance did not change significantly after bronchodilation despite a significant increase in FEV(1) of 0.18 (0.09) litres (p<0.001). A similar change in FEV(1) (0.18 (0.12) litres, p<0.001) was associated with a significant improvement in the distance walked on the endurance shuttle walk (Deltadistance ipratropium bromide--placebo = 144 (219) m, p = 0.03). Quadriceps muscle fatigue was infrequent (<15% of patients) after both walking tests.

CONCLUSION

The endurance shuttle walk is more responsive than the 6MWT for detecting changes in exercise performance following bronchodilation.

Effects of formoterol (Oxis Turbuhaler) and ipratropium on exercise capacity in patients with COPD

Although long-acting inhaled beta 2-agonists improve various outcome measures in COPD, no double-blind study has yet shown a significant effect of these drugs on exercise capacity. In a randomized, double-blind, placebo-controlled, crossover study, patients received formoterol (4, 5, 9, or 18 micrograms b.i.d. via Turbuhaler), ipratropium bromide (80 micrograms t.i.d. via pMDI with spacer), or placebo for 1 week. Main endpoint was time to exhaustion (TTE) in an incremental cycle ergometer test. Secondary endpoints were Borg dyspnoea score during exercise, lung function, and adverse events. Thirty-four patients with COPD were included, mean age 64.8 years, FEV1 55.6% predicted, reversibility 6.1% predicted. All doses of formoterol, and ipratropium significantly improved TTE, FEV1, FEF25-75%, FRC, IVC, RV and sGAW compared with placebo. A negative dose-response relationship was observed with formoterol. Ipratropium increased time to exhaustion more compared with formoterol, 18 micrograms, but not with formoterol, 4.5 and 9 micrograms. No changes in Borg score were found. There was no difference in the adverse event profile between treatments. In conclusion, 1 week of treatment with formoterol and ipratropium significantly improved exercise capacity and lung function compared with placebo. However, a negative dose-response relation for formoterol was unexpected and needs further investigation.

A systematic review of the effects of bronchodilators on exercise capacity in patients with COPD

One of the major goals of bronchodilator therapy in patients with COPD is to decrease airflow limitation in the airways and, as a consequence, improve dyspnea and exercise tolerance. The focus of this systematic review is to assess the effects of treatment with beta-agonists, anticholinergics, and theophyllines on dyspnea, and steady-state and incremental exercise capacity. Thirty-three, double-blind, randomized, placebo-controlled studies written in English were selected. This review shows that approximately half of the studies showed a significant effect of bronchodilator therapy on exercise capacity. Anticholinergic agents have significant beneficial effects in the majority of studies, especially when measured by steady-state exercise protocols. There is a trend toward a better effect of high-dose compared to low-dose anticholinergics. Short-acting beta(2)-mimetics have favorable effects on exercise capacity in more than two thirds of the studies; surprisingly, the situation is less clear for long-acting beta(2)-agents. The majority of the results of the published reports on theophyllines and their effects on exercise are negative. Direct comparisons of different classes of bronchodilators have not been made in a sufficient number of studies for a rational preference. The addition of a second bronchodilator has no proven advantage for improving exercise test results, but this has not been studied extensively and not in sufficiently large studies. The majority of studies reporting a measure of dyspnea found improvements, even in the absence of improvement in exercise capacity.

Evaluation of current pharmacotherapy of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a severe chronic respiratory condition characterised by progressive, irreversible airflow limitation. It is common, affecting more than 16 million people in the United States and is the fourth highest cause of death. The worldwide incidence of COPD is increasing and, in parallel, the economic and social burden the disease incurs. The treatment of COPD is symptomatic, with no drugs currently available to halt the relentless progression of airflow obstruction. However, with a better understanding of the pathological features of the airway inflammation and alveolar destruction that characterises COPD, new therapeutic strategies are being developed. This article provides a critical evaluation of current pharmacotherapy in COPD, essentially bronchodilators (anticholinergics, beta 2-adrenoceptor agonists and theophylline) and corticosteroids, and an overview of international recommendations for their use.