Aspirin-triggered pathway

Most people tolerate aspirin well, but not patients with asthma, of whom there is a subgroup in whom aspirin precipitates asthmatic attacks (61,62). This is a distinct clinical syndrome, called aspirin-induced asthma, which affects about 10% of adults with asthma (63). Aspirin-induced asthma is usually accompanied by naso-ocular symptoms and can be triggered not only by aspirin, but by several NSAIDs, a fact that makes immunological cross-reactivity most unlikely. The propensity of an NSAID to precipitate an attack of asthma is probably related to inhibition of COX (63). There is evidence that potent inhibitors of COX-1 (such as ibuprofen, indometacin, and naproxen) are more likely to precipitate bronchoconstriction than NSAIDs that inhibit COX-2 preferentially (such as meloxicam and nime-sulide) (64,65). A widely accepted hjrpothesis is that in patients with asthma and aspirin intolerance, NSAJD-induced COX inhibition results in increased products from the 5-lipoxygenase pathway, the leukotrienes, which are both potent bronchoconstrictors and also inducers of... 

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