Which class of medication is associated with causing lactic acidosis when undergoing a CT with contrast?

Lactic acidosis is a serious metabolic condition that can occur when there is an accumulation of lactic acid in the body. Metformin, a medication commonly used to manage type 2 diabetes, is particularly notable for its association with lactic acidosis, especially in specific situations such as renal impairment or when there is acute stress on the kidneys, which can be exacerbated by the use of iodinated contrast agents in CT scans.

When a patient on metformin undergoes imaging with contrast, the risk of lactic acidosis increases because the contrast media can lead to kidney dysfunction, potentially increasing the levels of metformin in the bloodstream. This situation can precipitate lactic acidosis since the drug affects the metabolism and clearance of lactic acid.

Other classes of medications mentioned, such as diuretics, beta blockers, and ACE inhibitors, are not associated with this particular side effect in the context of the use of contrast media. While they may have their own side effects, they do not carry the same risk of lactic acidosis in this clinical scenario. Therefore, metformin is recognized as the critical medication that requires caution in the context of contrast studies due to its association with lactic acidosis.