Constant P. van Schayck (Department of General Practice, Nijmegen University, the Netherlands): "We investigated the effects of chronic, continuous use of bronchodilators in asthma and chronic bronchitis. The possibly adverse effects of bronchodilators on the prognosis of asthma and chronic bronchitis is a topical subject nowadays. Long-term studies on this subject are scarce. These studies have begun to appear in the last few years, and they do not seem to justify the fear (or even panic) among patients and doctors of using these bronchodilators.
"It is true that several publications have pointed to the possibly adverse effects of these drugs. However, none of these publications have real-ly proved that bronchodilators are dangerous in the long run. In several epidemiological studies an association was found between the prescription of b2-adrenergic drugs and asthma mortality (J. Crane, et al., Lancet, 1:917-22, 1989; W.O. Spitzer, et al., New England Journal of Medicine, 326:501-6, 1992). These epidemiological studies cannot provide evidence for a causal relationship-- that is, that the bronchodilators themselves were the cause of an increase in asthma mortality. It is more probable that overdependence on the b2-adrenergic drugs delays the use of necessary anti-inflammatory agents and might therefore be a cause of asthma mortality.
"The only way to prove the deleterious effects of the bronchodilator itself is to perform clinical trials in which the treatment regimen is randomized. In this paper, we published the changes caused by continuous bronchodilator treatment compared with treatment on demand. The decline in lung function was 72 ml per year during continuous use and 20 ml per year during treatment on demand (p 0.05). Another prospective study showed an increased bronchial hyperresponsiveness during continuous use of a bronchodilator (M.R. Sears, et al., Lancet, 226:1391-6, 1990). On the basis of these studies it has been recommended that if asthmatic patients need to inhale a bronchodilator more than once daily, it is advisable to add anti- inflammatory medication.
"A follow-up study by our group investigated whether a rapid progression in lung function of patients with asthma or chronic obstructive pulmonary disease could be reversed or slowed by additional anti-inflammatory treatment (E. Dompeling, et al., Annals of Internal Medicine, 118:770-8, 1993). It was shown that the initial annual decline in FEV1 of 160 ml per year was decelerated to 100 ml per year during the use of the inhaled steroid. On the basis of these observations it is recommended to avoid overreliance on bronchodilators. The use of anti-inflammatory treatment (inhaled steroids or cromoglycate) should be given serious consideration when a bronchodilator is used daily."