COX Inhibition
When ASA is given, COX-1 and COX-2 are disabled, PGE2 synthesis stops and its modulating effects on mast cells and 5-LO are removed, and mediators are released or synthesized.
Leukotrienes are continuously and aggressively synthesized in patients with AIA before any exposure to NSAIDS/ASA, and during ASA-induced reactions, marked acceleration of synthesis occurs.
It is not known why interruption of PGE2 synthesis does not induce respiratory reactions in all humans.