Adverse effects of a single dose of (+)-sotalol in patients with mild stable asthma

Aims To investigate the effect of (+)-sotalol, which is not thought to possess clinically significant β-adrenoceptor blocking activity, on airway responsiveness in subjects with mild asthma.
Methods A placebo controlled, double-blind, single dose, cross over study, evaluating the effects of oral (+)-sotalol 300  mg and oral (±)-sotalol 240  mg, on airway responsiveness, FEV₁, and heart rate in 18 asthmatic volunteers with quantifiable levels of airway responsiveness.
Results Compared with placebo, (+)-sotalol induced a significant increase in airway responsiveness, and a significant decrease in FEV₁, but there was no significant change in heart rate. Following (±)-sotalol there was no significant effect on airway responsiveness, but there were significant decreases in FEV₁ and heart rate. In one subject both (+)-sotalol and (±)-sotalol provoked a 49% decrement in FEV₁, and in another there were decrements of 20% and 18%, respectively.
Conclusions Despite theoretical considerations, it cannot be assumed that (+)-sotalol is safe in patients with asthma.