Effect of CI-922, a potential new antiallergy agent, on arachidonic acid metabolism in vitro.

CI-922 (3,7-dimethoxy-4-phenyl-N-1H-tetrazol-5-yl-4H-furo[3,2-b]indole-2- carboxamide, 1,2-ethanediamine, 2:1), an antiallergy compound, was tested for its effects on arachidonic acid metabolism, and its potency was compared to that of proxicromil, BW-755C, indomethacin, and nordihydroguaiaretic acid (NDGA). CI-922 was both a relatively potent and selective inhibitor of 5-HETE and LTB4 formation in human leukocytes, being equipotent to BW-755C and about four-fold more potent than proxicromil. However, CI-922 was rather weak in inhibiting the formation of PGE2 in bovine seminal vesicles. The parallel inhibition of 5-HETE and LTB4 formation by CI-922 suggests that either direct or indirect inhibition of the 5-lipoxygenase pathway may explain, at least in part, its antiallergy properties.