The new prescriptions are: "Abdominal CT with contrast in AM of 2/3" and "Increase quinapril to 40 mg PO daily." What is the nurse's rationale for holding metformin for the next four days on the client's MAR?

Nursing management of clients receiving contrast imaging requires careful medication review to prevent adverse renal complications. Metformin is commonly held around the time of iodinated contrast administration because of the risk of contrast-induced nephropathy and subsequent lactic acidosis. When renal function is temporarily impaired, metformin can accumulate in the body and lead to a rare but serious complication. Therefore, timing of withholding and restarting the drug is critical for patient safety. Rationale: A. Metformin does not need to be held when the dose of quinapril is increased. While ACE inhibitors like quinapril can affect renal perfusion, there is no standard requirement to discontinue metformin solely due to dose adjustment of this medication. The concern is specifically related to renal function and contrast exposure, not antihypertensive titration. B. Holding metformin because the client may leave the facility is unrelated to pharmacologic safety guidelines. Medication withholding must be based on clinical indications, not potential discharge or travel plans. Temporary absence from the facility does not require stopping metformin therapy. C. The client requesting a break from metformin due to acceptable blood glucose levels is not a valid clinical reason to discontinue the medication. Even when glucose levels are within range, ongoing therapy is usually needed to maintain glycemic control. Medication changes should be based on provider assessment, not patient preference alone. D. Metformin must be held 1–2 days before and 2 days after administration of intravenous contrast medium because contrast agents can impair kidney function. Reduced renal clearance increases the risk of metformin accumulation, which may lead to lactic acidosis, a life-threatening condition. Holding the medication allows time for renal function to stabilize before resuming therapy.