The role of cysteinyl leukotrienes in the pathogenesis of asthma: clinical study of leukotriene antagonist pranlukast for 1 year in moderate and severe asthma.

Clinical studies have shown that pranlukast (Ono Pharmaceutical Co., Osaka, Japan) is effective for mild and moderate asthma. However, it is not well known that pranlukast is also effective on moderate and severe persistent asthma in the long term. We studied the effect of pranlukast on moderate and severe asthmatics by evaluating the change of peak expiratory flow (PEF) and therapeutic scores for 1 year before and during pranlukast therapy. We gave pranlukast 225 mg twice daily orally to 25 patients who were receiving more than 400 micrograms/day beclomethasone inhalation and beta 2 stimulant inhalation with or without oral corticosteroid. Pranlukast increased PEF more than 10 L/min in 14 patients in the first 4 weeks. In these 14 patients, 10 patients continued to monitor PEF and kept asthma diaries for 1 year. We compared the data for 1 year before and during the pranlukast therapy. During the pranlukast therapy, PEF significantly increased, puffs of beta 2 stimulant inhalation significantly decreased. The incidence of oral corticosteroid rescue therapy reduced, and the mean daily dose of oral corticosteroid decreased; however, they were not statistically significant. During treatment with pranlukast, no side effect was observed. From these results, we suggest that pranlukast is effective for more than half of the moderate and severe persistent asthmatics, and that the effectiveness continues for more than 1 year.