Delay of Onset of Symptoms of Japanese Cedar Pollinosis by Treatment with a Leukotriene Receptor Antagonist

Background: Leukotriene receptor antagonists (LTRAs) are effective for prophylactic treatment of pollinosis based on studies showing that administration of LTRAs prior to or at the start of the pollen season reduces symptoms and QOL disturbance at the peak of pollen dispersal. Two goals of prophylactic treatment of pollinosis are use of fewer types of drugs and delay of onset of symptoms and impairement of QOL. Therefore, this study was performed to determine if pranlukast, a LTRA, met these goals in treatment of pollinosis. Methods: Pranlukast or placebo was administered to patients who visited our hospital immediately before the start of Japanese cedar pollen dispersal. The study was performed for 4 weeks as a double blind randomized trial. Subsequently, all patients were given pranlukast for a further 4 weeks from the peak until the end of pollen dispersal. The incidence of symptoms and use of concomitant drugs were investigated from daily nasal allergy records kept by patients. QOL was evaluated using the JRQLQ questionnaire. Results: In the double blind period of the study, the percentage of patients who used concomitant drugs for nasal symptoms was significantly lower in the pranlukast group compared to the placebo group. Development of nasal symptoms (sneezing, runny nose and nasal congestion) and disturbance of daily activities were significantly delayed in the pranlukast group. No serious adverse reactions occurred in the pranlukast group and no patient withdrew from treatment with pranlukast. Conclusions: Pranlukast is effective for prophylactic treatment of pollinosis