Metformin toxicity

Q: The primary goal of  hemodialysis (HD) in Metformin toxicity is to clear the drug from circulation? (select one)

A) True
B) False


Answer: B

Metformin toxicity is unique in many ways. 

First, the dose of intake does not correlate with the level of toxicity. 

Second, Metformin by itself rarely cause the hypoglycemia, so other causes of hypoglycemia should be sought. 

Third, sodium bicarbonate in metformin-induced lactic acidosis is not very much recommended as it has shown to cause reflex vasodilation after the bolus injection. 

Fourth, the objective of HD in metformin is not to remove the drug but to blunt the acidosis, so patients may require repeat treatments. For this reason HD should be performed with bicarbonate buffer. 

 HD should be strongly considered in patients with lactate level more than 15 mmol/L, pH less than 7.10, failure to respond to conventional treatment, hemodynamic stability, liver failure, encephelopathy or kidney function deterioration.


#toxicology
#nephrology
#pharmacology


References:

1. Calello DP, Liu KD, Wiegand TJ, et al. Extracorporeal Treatment for Metformin Poisoning: Systematic Review and Recommendations From the Extracorporeal Treatments in Poisoning Workgroup. Crit Care Med 2015; 43:1716. 

2. Seidowsky A, Nseir S, Houdret N, Fourrier F. Metformin-associated lactic acidosis: a prognostic and therapeutic study. Crit Care Med 2009; 37:2191. 

3. Heaney D, Majid A, Junor B. Bicarbonate haemodialysis as a treatment of metformin overdose. Nephrol Dial Transplant 1997; 12:1046. 

4. Dell'Aglio DM, Perino LJ, Kazzi Z, et al. Acute metformin overdose: examining serum pH, lactate level, and metformin concentrations in survivors versus nonsurvivors: a systematic review of the literature. Ann Emerg Med 2009; 54:818. 

5. Lalau JD, Andrejak M, Morinière P, et al. Hemodialysis in the treatment of lactic acidosis in diabetics treated by metformin: a study of metformin elimination. Int J Clin Pharmacol Ther Toxicol 1989; 27:285. 

6. Rifkin SI, McFarren C, Juvvadi R, Weinstein SS. Prolonged hemodialysis for severe metformin intoxication. Ren Fail 2011; 33:459.