Adverse reactions to intravascular administration of contrast media.

Adverse reactions to intravascular administration of contrast media, while low in incidence, merit serious consideration in view of increased utilization of these substances all over the world. Evidence for involvement of soluble mediators, antibody-antigen reactions, psychogenic factors, and the acute activation systems, is reviewed. As a group, the pre-contrast challenge plasmas of reactors are characterized by slightly diminished concentrations of Cl-esterase inhibitor and total hemolytic complement, and by an accelerated rate of conversion of prekallikrein to kallikrein on exposure to contact activators. The role of intravenous pretesting and pretreatment is considered. A rationale for pretreatment with adrenocorticosteroids is presented.