CAMRT Radiography Practice Exam

Which drug should be discontinued 48 hours after administration of water soluble iodinated contrast media?

1. Insulin

2. Metformin

3. Beta-blockers

4. Glucagon

The correct answer is: Metformin

Water-soluble iodinated contrast media can cause kidney function impairment, particularly in patients with pre-existing renal conditions. Metformin is an oral hypoglycemic agent commonly used in the management of type 2 diabetes. One of the critical considerations when using contrast media in patients who are taking metformin is the risk of lactic acidosis if renal function declines. If metformin is continued after the administration of iodinated contrast, and if the patient's kidney function is compromised, the drug can accumulate and potentially lead to fatal levels of lactic acid in the blood. Thus, it is recommended to discontinue metformin at the time of the contrast administration and to hold off on its use for at least 48 hours afterward to ensure the patient's renal function is stable and to reduce the risk of complications. In contrast, other options like insulin, beta-blockers, and glucagon do not have the same immediate risk of complications following contrast media administration, and therefore they do not have an established guideline for discontinuation for a specified time after the use of iodinated contrast agents. This is why metformin is specifically highlighted as needing to be stopped after the use of contrast media, making it the correct choice.