Metformin lactic acidosis and anaesthesia: myth or reality?

To determine whether a causal or coincidental relationship is indicated in the literature between metaformin and lactic acidosis and to recommend clinical guidelines for the withdrawal of metformin prior to surgery.

A broad review of the literature related to metformin associated acidosis was carried out. (There are few publications specifically related to metformin treatment and anaesthesiology).

When metformin-associated lactic acidosis occurs, a concurrent pathology or contraindication to the use of metformin is often found. Anaesthesia and surgery can generate or aggravate concurrent pathologies.

Although no association has been shown between metformin and lactic acidosis under usual conditions of use, vigilance is required when metformin is used prior to surgery. The following clinical guideline is proposed: to withdraw (when possible) metformin 48 hours prior to surgery and to wait until the patient's biological and clinical parameters return to normal before reintroducing it.