Analgesics, allergy and asthma.

1 Recent studies of idiosyncratic reactions to analgesics have revealed several clinical patterns with a different pathogenesis. 2 In the pathogenesis of a common type of asthma precipitated by aspirin, inhibition of cyclooxygenase leading to disturbances in metabolism of arachidonic acid is of fundamental importance. 3 In some patients with urticaria/angioedema, symptoms are due to inhibition of cyclo-oxygenase by analgesics; in others the cause might be impurities in commercial preparations of aspirin; and in others the mechanisms are still unknown. 4 There is a distinct group of patients who develop anaphylactic shock or urticaria following administration of pyrazolone drugs, but who tolerate aspirin and other cyclo-oxygenase inhibitors. This type of hypersensitivity seems to have an immunological background.