Frequency and severity of adverse effects of iodinated and gadolinium contrast materials: retrospective review of 456,930 doses.

OBJECTIVE: The purpose of this study was to determine the frequency and characteristics of adverse effects of low-osmolar iodinated and gadolinium contrast agents in a single-center experience with a large number of cases.

MATERIALS AND METHODS: A retrospective review of all intravascular doses of low-osmolar iodinated and gadolinium contrast materials administered from 2002 through 2006 was conducted. Adverse effects were identified through the use of radiologist and nurse event recording. Adverse effects were examined for type and severity of reaction, treatment required, and outcome.

RESULTS: A total of 456,930 contrast doses (298,491 low-osmolar iodinated, 158,439 gadolinium) were administered over the study period. A total of 522 cases of adverse effects (0.11% of total) were identified (458 low-osmolar iodinated, 64 gadolinium). The most common adverse effects were hives (274, 52.5%) and nausea (92, 17.6%). Of all adverse effects, 79 of low-osmolar iodinated and 15 of gadolinium contrast material necessitated treatment. Most treatments were performed in the radiology department alone. Only 16 cases of adverse effects necessitated transfer for further observation or treatment. Epinephrine was used to manage an adverse effect in nine instances. Thirty-two of the adverse effects of low-osmolar iodinated contrast material (6.9%) occurred in patients with a history of allergy who received premedication. Only two of these premedication reactions necessitated transfer to the emergency department. The one death in the study period occurred after administration of low-osmolar iodinated contrast material. The patient had no symptoms during the contrast administration or imaging but died suddenly within 30 minutes of receiving the dose.

CONCLUSION: Both iodinated and gadolinium contrast agents are associated with a very low rate of adverse effects. Most adverse effects are mild and can be managed in the radiology department. Transfer for additional treatment or observation is rarely needed.