Your patient is being prepped for a procedure tomorrow morning that requires an IV contrast medium. While reviewing the patient's home medications he notices which medication should be discontinued temporarily in preparation for this procedure?

A. The sulfonylurea, glipizide: Glipizide does not interact with IV contrast media and does not increase the risk of contrast-related complications. It is generally continued unless the patient will be NPO for an extended period. B. Short-acting regular insulin: Insulin does not interact with IV contrast media. Dosing adjustments may be needed if the patient is NPO, but insulin is not discontinued due to contrast administration. C. The meglitinide, repaglinide: Repaglinide does not pose a risk when IV contrast is administered. Like other short-acting antihyperglycemics, it may be held if the patient is not eating, but not because of contrast exposure. D. The biguanide, metformin: Metformin is temporarily discontinued before and after IV contrast administration due to the risk of lactic acidosis if contrast-induced nephropathy occurs. Renal function is reassessed before restarting the medication to ensure patient safety.