Metformin is an oral antihyperglycemic medication administered alone or in combination. There have been case reports of patients developing lactic acidosis after receiving iodinated contrast material while on metformin. Therefore, if a patient is on metformin, or a metformin containing medication, determine which of the two following categories describes the patient’s situation:

  1. No evidence of acute kidney injury and an eGFR ≥ 30.  In this setting, metformin can be continued and there is no need to reassess renal function.
  2. Acute kidney injury or severe chronic kidney disease (stage IV or stave V, eGFR <30) OR arterial catheter studies that might result in emboli to the renal arteries. In this setting, metformin should be held 48 hours after the contrast bolus/procedure. Renal function should be reassessed 48 hours after the contrast load; if renal function is normal (or at baseline), metformin may be restarted.
  3. Metformin and Gadolinium: It is not necessary to discontinue metformin prior to contrast medium administration when the amount of gadolinium-based contrast material administered is in the usual dose range of 0.1 to 0.3 mmol per kg of body weight.

List of Metformin-containing Medications