emDocs - December 2, 2015 - Authors: Moleno R and Haynes A - Edited by: Koyfman A and Alerhand S
"Background
Metformin, a biguanide derived from guanidine, was introduced in the 1950’s as a treatment for diabetes, and remains widely used today with 40 million prescriptions filled worldwide in 2008 (1). Lactic acidosis is the primary toxicity of concern, with an estimated incidence of 0.03 per 1000 patients/year (2). Metformin-associated lactic acidosis may happen with therapeutic doses or after an acute overdose. Currently the data is mixed as to which situation leads to a more severe pattern of illness. Common initial symptoms are non-specific and include nausea, vomiting, diarrhea, abdominal pain, malaise, and decreased oral intake. In severe cases, altered mental status, tachypnea, hypothermia or cardiovascular collapse may occur.
Major Points
- MALA is a rare but life-threatening condition seen after use of Metformin. The condition should be considered in patients who present with elevated lactate (>5 mg/L) and acidemia.
- Get your local toxicologist involved early, as it carries a high mortality, up to 50%.
- The management is mainly supportive, but Metformin use must be stopped and intravenous bicarbonate can be infused to correct severe acidosis.
- Renal replacement therapy can be used to remove the drug and also to correct the acidosis. If you are not at a facility that has hemodialysis capabilities, you should transfer the patient to a center capable of this higher level of care.
- Survivors tend to regain kidney function."
http://www.emdocs.net/metformin-associated-lactic-acidosis-mala-ed-focused-management/