[Inhibitor of chemical mediator release]

Since tranilast, the first inhibitor of chemical mediator (ICMR), had been assessed to be as effective as disodium cromogycate in asthma, several orally active ICMRs, which have no antihistamine or bronchodilator effect, have been developed and prescribed for asthma control in Japan. On the other hand, as histamine H1-antagonists (H1-antagonists) have been shown to inhibit mediator release from mast cells in vitro, these drugs are sometimes classified as ICMR. ICMRs are effective in 40% of asthmatics but it takes 6 or more months for these drugs to improve the symptoms clearly. Although H1-antagonists are effective in only about 30% of asthmatics, they have been shown to be more effective on cough of asthma, cough variant asthma and atopic cough. H1-antagonists have been shown to strongly inhibit alcohol-induced asthma which is evoked in 60% of Japanese asthmatics.