Emergency administration of radiocontrast media in high-risk patients.

Patients with previous anaphylactoid reactions to radiographic contrast media (RCM) are at increased risk for subsequent reactions on repeat exposure. The most efficacious pretreatment regimens require administration of medications up to 13 hours before the anticipated procedure. Emergency administration of RCM in patients requiring essential procedures precludes prolonged pretreatment. We report results of pretreatment in nine patients requiring emergency administration of RCM. We recommend hydrocortisone, 200 mg intravenously, immediately, and every 4 hours until the procedure is completed, and diphenhydramine, 50 mg intravenously, 1 hour before the procedure. No reactions occurred in these patients, suggesting that this pretreatment regimen may be valuable in prophylaxis for patients requiring emergency administration of RCM who have experienced previous anaphylactoid reactions. Although used in only one additional patient, ephedrine, 25 mg orally, 1 hour before the procedure may also be valuable.