Iohexol in patients undergoing urography: a comparison of polypropylene containers (Unique Soft Pack) and glass vials

The purpose of the present phase IV multicentre trial was to evaluate general patient tolerance to Omnipaque 350 mgI/ml (iohexol) supplied in polypropylene containers compared to that of the same product supplied in routinely used glass vials, with emphasis on allergy-like adverse events. Polypropylene is a pure plastic material with practically no additives, and has been tested in vitro as a contrast medium packaging material for several years. Handling of these containers is easier and safer than handling of glass vials. Iohexol was administered to 1481 patients undergoing urography (741 patients in the glass vial group, 740 in the polypropylene container group), all of whom successfully participated in the trial. Six centres, representing four European countries, participated. Patients were randomized to receive iohexol from either polypropylene containers or traditional glass vials according to a double blind, parallel design. Pre-established inclusion and pre-admission exclusion criteria were followed, as well as routine procedures for preparation of the patients and conduct of the urography examinations at each hospital. Patient tolerance was assessed by recording all adverse events experienced over a period of up to 1 h after the procedure. Allergy-like events were defined as coughing, sneezing, nausea, vomiting, urticaria or itching. No adverse events were experienced by 56.5% of the patients in the glass vial group, nor by 58.0% of those in the polypropylene group. Discomfort (mainly a sensation of warmth) was reported by 39.4% and 38.6% of the patients, and adverse events other than discomfort by 7.4% and 5.9% of the patients, respectively. There seemed to be a correlation between the speed of injection and the frequency of discomfort (an increase with increasing speed), both of which varied a lot between centres. There was no significant difference in the incidence of allergy-like events between the two groups. Such reactions were seen in 2.0% of patients in the glass vial group and 1.9% of those in the polypropylene container group. There was no significant difference between the patients' tolerance to iohexol supplied in traditional glass vials or in polypropylene containers. Therefore, the new polypropylene container can be recommended as a container for Iohexol.