the relative order of potency ( antianaphylactic activity ) at calculated ic50 level was as follows : fpl 55712 ( a leukotriene receptor antagonist ) greater than nordihydroguaiaretic acid ( a lipoxygenase inhibitor ) greater than p-bromophenacyl bromide ( a phospholipase a2 inhibitor ) greater than bw 755c ( a dual inhibitor of lipoxygenase and cyclo-oxygenase ) greater than theophylline ( a phosphodiesterase inhibitor ) greater than azelastine greater than diphenhydramine ( h1 histamine-receptor antagonist ) greater than ketotifen greater than disodium cromoglycate .
C2919009
h1 histamine-receptor antagonist
C0022642
ketotifen