RDJ is a 50-year-old man with type 2 diabetes mellitus who i…

RDJ is a 50-year-old man with type 2 diabetes mellitus who is taking metformin (Glucophage) and sitagliptin (Januvia). His blood glucose is well-controlled at this time. He is scheduled for a CT scan of the abdomen with IV contrast. Which of these actions is MOST appropriate?