[Metformin and contrast media--increased risk of lactic acidosis?]

A rare side effect from metformin is lactic acidosis. There have been much concern about the reported risk when metformin was combined with contrast medium. Almost all reported cases following combination with contrast media occurred when pre-existing poor renal function was present. A recent review of the literature has resulted in new recommendations in Europe and the USA. We suggest new guidelines for Norway with regard to the use of metformin in patients undergoing radiological examination with contrast media.