Effect of zafirlukast on cough reflex sensitivity in asthmatics

In patients with asthma, increased sensitivity of airway sensory nerves may be involved in producing bronchospasm and cough. To evaluate the effect of a leukotriene-modifying agent on cough reflex sensitivity, we measured the cough response to inhaled capsaicin before and after a 14-day course of therapy with zafirlukast, a cysteinyl leukotriene receptor antagonist, in a group of stable asthmatics. The concentration of capsaicin inducing two or more (C₂) and five or more (C₅) coughs was not altered by zafirlukast, even in those subjects demonstrating a significant change (increment or decrement) in forced expiratory volume in 1 sec (FEV₁). These findings support previous evidence that cough and bronchoconstriction are modulated by distinct neural pathways.