Radiographic contrast media studies in high-risk patients.

Patients with prior anaphylactoid reactions (AR) to radiographic contrast media (RCM) are at increased risk for another reaction upon repeat exposure to RCM. One hundred one patients, who had prior AR to RCM, who gave informed consent, and who had an essential need for a repeat RCM study, were pretreated with prednisone, 50 mg orally every 6 hours for 3 doses ending one hour prior to RCM study, and diphenhydramine, 50 mg intramuscularly, one hour prior to RCM study. The repeat RCM study was then carried out using standard procedures with resuscitation equipment readily available. Ninety-six patients had no reaction. Five of the 101 (4.95%) developed AR. These AR consisted only of mild urticaria or pruritus. No significant or life-threatening reactions occurred. Pretreatment decreases the risk in this population of patients and is recommended as standard prophylaxis for patients requiring RCM who have had a previous AR.