Therapeutic reduction of ongoing carrageenin-induced inflammation by lipoxygenase, but not cyclooxygenase inhibitors.

A variety of steroidal and nonsteroidal antiinflammatory agents (NSAs) were compared for their effectiveness against a developing acute inflammatory reaction. Only BW 755C [3-amino-1-(m-trifluoromethyl)-phenyl-2-pyrazole] was immediately effective when administered 2 h after carrageenin, as the 3-h swelling was significantly reduced. Dexamethasone, a steroidal antiinflammatory agent, produced a delayed reduction. When administered at 2 h postcarrageenin, there was no effect at 3 h; but at 6 h, dexamethasone significantly reduced the swelling. In contrast, neither of the classic NSAs, aspirin or indomethacin, were effective when administered after the carrageenin. The results demonstrating a postcarrageenin effectiveness by BW 755C and dexamethasone are discussed as a possible reflection of an action on the lipoxygenase pathways of the arachidonic cascade that is not shared by the classic NSA.