Continue taking metformin as prescribed

Are you sure? Remember that metformin, a renally excreted drug, can increase the risk of lactic acidosis, in cases of impaired kidney function. Contrast exposure is associated with nephrotoxic effects and metformin use during this time can increase Mr. Green’s risk of lactic acidosis. It is reasonable to continue metformin after the procedure once creatinine/eGFR are confirmed unchanged and the patient is clinically stable.