Dose-response relationships in determining the safety:efficacy ratio

The development of inhaled agonists selective for beta 2-adrenoceptors and high potency corticosteroids has improved the treatment of asthma. The delivery of the drugs to the site of action reduces the systemic exposure and hence reduces adverse systemic events. Together, these factors have resulted in improved toxicity: therapeutic ratios. Long-acting beta 2-agonists, such as salmeterol and formoterol, and high efficacy corticosteroids, such as fluticasone propionate and budesonide, now are available for clinical use. Because suboptimal treatment of asthma causes increased morbidity and mortality, and increased costs to society, these compounds are of particular value. Risk factors associated with fatal and near-fatal asthma have been identified, and it would appear that drug treatment by metered dose inhaler per se does not cause increased asthma fatality as an independent risk factor.