Effects of on-demand beta2-agonist inhalation in moderate-to-severe asthma. A randomized controlled trial.

BACKGROUND: The appropriate use of short-acting beta2-agonist inhalation in asthma has been the subject of controversy in recent years. Limited information is available for the group of moderate to severe asthmatics with high intake of bronchodilator inhalants and continuous anti-inflammatory protection.

OBJECTIVE: To investigate the effects of beta2-agonist reduction in marked asthma treated with multiple asthma medications.

DESIGN: Randomized, controlled single-blind, cross-over trial.

SETTING: Outpatient clinic at a university medical centre.

SUBJECTS: A total of 80 adult patients with moderate-to-severe asthma.

INTERVENTIONS: In a 1-year study patients were assigned to on-demand vs. regular beta2-agonist inhalation treatment.

MAIN OUTCOME MEASURES: Asthmatic episodes (primary outcome), symptoms, peak expiratory flow rates (PEF) and drug use were recorded daily. Bronchodilator and airway responsiveness, lung function indices and quality of life were assessed during five clinic visits. Also, practicability of beta2-agonist tapering in multimedicated asthmatics was analysed.

RESULTS: More than 80% of moderate-to-severe asthmatics were able to reduce their beta2-agonist intake by >/=50%. Puffs per day of active therapy decreased from 7.9 in regular to 3.3 in on-demand treated patients (P = 0.0001). The type of beta2-agonist used (salbutamol/fenoterol) had no significant impact on the study findings. Almost all parameters of control of asthma improved during the on-demand treatment period.

CONCLUSION: On-demand inhalation of short-acting beta2-agonists in moderate-to-severe asthma is safe, and even in severe asthma a reduction from regular to on-demand beta2-agonist inhalation is possible, with improved asthma control.