Metformin media

All patients admitted to a hospital during 6 months who had taken at least one dose of metformin were retrospectively evaluated for susceptibility factors for metformin-associated lactic acidosis (8). There were 263 hospitalizations in 204 patients. In 71 admissions there was at least one contraindication, such as renal or liver disease, renal dysfunction, congestive cardiac failure, metabolic acidosis, or an intravenous iodinated contrast medium given within 48 hours of metformin. In 29 (41%) metformin was continued despite the contraindication. The most frequent contraindication was a raised serum creatinine, but in only eight of the 32 admissions was metformin withdrawn. Of nine patients using metformin who died (not necessarily directly related to metformin), six had an absolute contraindication. In two patients who died and in one who survived, blood lactate was increased and this was temporally related to the use of metformin. 

Radiocontrast media can induce acute renal insufficiency in patients taking metformin (139,140). Metformin should be withdrawn 2 days before an iodinated contrast medium is given (SEDA-21, 445) and the following protocol has been suggested (141) ... 

Discontinue nephrotoxic drugs—Nonsteroidal antiinflammatory drugs and diuretics should be withheld for at least 24 hours before and after exposure to contrast medium, if possible. Metformin should be withheld for 48 hours before the administration of CM and until it is certain that CIN has not occurred. 

The Royal College of Radiologists. Guidelines with regard to metformin-induced lactic acidosis and x-ray contrast medium agents. 19 March 1999. 

Goergen SK, Rumbold G, Compton G, Harris C. Systematic review of current guidelines and their evidence base on risk of lactic acidosis after administration of contrast medium for patients receiving metformin. Radiology 2010 254 261-9. 

---