Final answer:
Metformin is usually discontinued on the day of IV iodine contrast exposure to prevent the risk of lactic acidosis, a serious condition, due to the potential impact of the contrast media on kidney function which affects metformin accumulation.
Step-by-step explanation:
The discontinuation of metformin on the day of IV iodine contrast exposure is a precautionary measure taken to prevent the risk of a rare but serious condition known as lactic acidosis. When a patient is due to receive IV iodine contrast, typically for diagnostic imaging procedures, metformin, which is a medication used to control blood sugar in people with type 2 diabetes, is temporarily stopped. The reason behind this is the potential for iodine contrast media to cause a decrease in kidney function, which could lead to an accumulation of metformin in the body and result in increased risk of lactic acidosis.
Guidelines generally recommend that patients on metformin should stop taking the medication at the time of or before their contrast procedure and should not resume it for 48 hours after, pending reassessment of renal function. It's vital for patients to follow their healthcare provider's instructions regarding metformin and contrast exposure to ensure safety and appropriate medical care.