We present results of a postmarketing surveillance study with iobitridol (Xenetix, Sulzbach, Germany) in more than 61,000 patients from 1996 until 2000. The purpose of this study was the assessment of safety and diagnostic efficacy of the non-ionic contrast agent iobitridol in the setting of a post-marketing surveillance study. Iobitridol (Xenetix) has been registered in Germany since 1996. Between 1996 and 2000 207 radiologists have documented in a questionnaire the routine use of Xenetix in 61,754 patients that have received Xenetix for diagnostic procedures. On each questionnaire parameters regarding demographic data, safety, and diagnostic efficacy were assessed. The data were statistically evaluated and analysed. The examination allowed for a diagnosis in 99% of cases. Image quality was rated as "excellent" or "good" in 89.8% of cases. In obese patients there was a significantly higher percentage ( p<0.001) of poor image quality. In 0.1% poor contrast was noted. Of patients, 28.8% had at least one risk factor, and 3.1% had three or more. Adverse events were noted in 2.3% of the examinations, but nearly half of them (1.1%) presented with "feeling of warmth" as the only symptom. Of adverse events, 0.2% were non-transient, and 1 patient died. In 0.2% of patients the procedure was stopped due to adverse events. In 0.9% of patients the causal relationship with the contrast agent was rated as probable (probable+possible=1.1%). The percentage of adverse events (excluding warmth) was independent of iodine concentration and of dose, and was higher in young patients. Xenetix is an efficient contrast agent for radiological procedures and is associated with a low rate of adverse events.

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.