Prophylaxis against repeated radiocontrast media reactions in 857 cases. Adverse experience with cimetidine and safety of beta-adrenergic antagonists.

Eight hundred fifty-seven radiocontrast media (RCM) procedures were performed from 1974 to 1984 in 743 patients who previously had experienced an immediate generalized (anaphylactoid) reaction to RCM. During the 695 intravascular infusions of RCM, prednisone-diphenhydramine hydrochloride pretreatment of 415 essential repeated RCM procedures from 1974 to 1980 resulted in 45 (10.8%) reactions during which transient hypotension occurred in three (0.7%) patients. From 1980 to 1983, prednisone-diphenhydramine-ephedrine sulfate pretreatment of 180 procedures was associated with only nine reactions (5.0%) (chi 2 = 5.195). The addition of cimetidine hydrochloride in 1983 to 1984 was not useful in that 14 reactions occurred during 100 procedures (14.0%). The 21 patients who had been receiving beta-adrenergic antagonist therapy were protected as well as those who were not, in that none of 11 patients receiving the three-drug regimen had a repeated reaction and only one of ten patients receiving the four-drug regimen reacted.