Short-acting β-agonist (SABA) drugs have been mainstays of asthma therapy for many decades and are recommended treatment at all levels of asthma severity, as they provide prompt relief of asthma symptoms through smooth muscle relaxation and, thereby, bronchodilatation. At all levels of asthma severity more severe than mild intermittent, SABAs are recommended to be taken as required for relief of symptoms in conjunction with inhaled corticosteroids (ICSs) taken as regular maintenance treatment. However, in mild asthma SABAs are recommended as monotherapy without concomitant ICS therapy, and in both mild and more severe asthma, greatly increased SABA use at times of asthma exacerbation is almost universal. Here we discuss the safety of inhaled β-agonist monotherapy in asthma and argue against the continued use of β-agonist monotherapy (both short and long acting) in the absence of concomitant ICS therapy in a combination inhaler.

Several epidemiological studies link overuse of SABA therapies at times of asthma exacerbation with increased risk of hospitalisation or mortality.1 2 The mechanisms underlying this increased risk have not been clearly determined, but are most likely to involve complex mechanisms including delays in seeking medical care, potential cardiac (tachycardia) and metabolic (hypokalaemia) adverse effects as well as possible effects on underlying asthma severity. Although fenoterol, the SABA linked with the epidemic of asthma mortality in the early 1980s in New Zealand3 and some other countries,4 has greater cardiac effects than other SABAs, the reduction in hospitalisations due to asthma exacerbations (along with a reduction in asthma mortality) following the withdrawal of high dose fenoterol in New Zealand in 1990 suggested that the reduction in asthma mortality was not wholly due to reduction in cardiac/metabolic side effects, but probably also due to an effect on disease severity (because if the reduction in mortality were due to reduction …