- metformin use is associated with lactic acidosis, but it remains controversial as a disease entity
- the mechanism of lactic acidosis is uncertain
Metabolic effects of metformin include:
- decreased gluconeogenesis
- increased peripheral glucose uptake
- decreased fatty acid oxidation
- presence of risk factors
- abdominal pain
- nausea and vomiting
- altered mental status
- myocardial insufficiency
- multi-organ failure
- advanced age
- high dose
- renal failure (metformin is excreted unchanged in the urine)
- active alcohol intake
- high anion gap metabolic acidosis (HAGMA)
- high lactate
- rule out other causes of lactic acidosis (sepsis, cardiogenic shock, hypoperfusion, ischaemic bowel)
- withdrawal of metformin
- remove metformin and correct acidosis
- best performed early due to large volume of distribution of metformin
- use hemodialysis
- use HCO3 buffer
- Some argue that metformin itself does not cause lactic acidosis, that it is actually due to the underlying conditions such as renal failure and diabetes mellitus.
- However, there are definite cases of lactic acidosis from acute metformin overdose with no other underlying risk factors.
References and Links
- Orban JC, Fontaine E, Ichai C. Metformin overdose: time to move on. Crit Care. 2012 Oct 25;16(5):164. PMC3682282.
- Salpeter SR, Greyber E, Pasternak GA, Salpeter EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev. 2010 Apr 14;(4):CD002967. PMID: 20393934.
FOAM and web resources
- TPR — Metformin Overdose Quiz (2012)