Intravenous Contrast Media in Uroradiology: Evaluation of Safety and Tolerability in Almost 50,000 Patients

Ojective: To evaluate the frequency of adverse events and possible risk factors after the administration of an intravenous contrast medium (CM), iobitridol, in a large multicentre postmarketing surveillance study. Subjects and Methods: A total of 49,975 patients undergoing intravenous urography were included in this study. A water-soluble, non-ionic CM (iobitridol, 1 ml/kg body weight) was administered. Age, sex, indication for the actual examination and adverse events were documented. Also, high-risk patients were identified. Results: Of the 49,975 patients, 28,336 (56.7%) were males and 21,639 (43.3%) females. Indications for urography were mainly urolithiasis (39.1%), inflammatory diseases (25.6%) and tumours (13.9%). Additionally, 7.4% were risk patients: 1.9% with creatinine 1.5 mg/dl (0.1% were on haemodialysis); 0.8% had a history of previous allergic reactions to CM, 3.7% pre-existing asthma or allergies and 2% other risk factors against CM examination. Only 0.9% of the patients experienced acute adverse events that were non-serious and transient. Less than 0.1% of the patients experienced vomiting, dizziness or cardiovascular problems. Only 1 patient developed an anaphylactic shock but recovered fully under treatment. A χ2 analysis revealed that adverse reactions occurred in patients with pre-existing renal insufficiency or allergies. Significantly more females had contrast-agent-related symptoms compared to men. Patients undergoing urography for urolithiasis had significantly fewer symptoms compared to patients with other indications. Conclusion: Iobitridol is clinically safe and well tolerated in urography as demonstrated in this study of a large patient population, producing mainly minor symptoms as adverse events. However, caution is advised when administering iobitridol to high-risk patients.