Objective: Over decades, Metformin was accused of causing lactic acidosis in end–stage renal disease (ESRD) patients and in spite of its well known benefits; its use in this group of patients is still restricted. Little is reported about the effect of hemodialysis (HD) on metformin clearance and the fear of lactic acidosis deprives ESRD patients from metformin therapeutic advantages. Dialysis in general and HD in particular may save ESRD patients from this hazard.  

Material and Methods: The study was conducted on 61 HD patients with type–2 diabetes mellitus in 3 centers. Metformin was administered in a single dose 0f 250–500 mg three times weekly post HD. Patients were monitored for glycemic control. Plasma lactic acid and plasma metformin levels were monitored on a scheduled basis. The relation between plasma metformin and plasma lactate was studied in addition to the effect on mortality.

Results: Mean fasting blood sugar (FBS) was 12.4 + 0.5 and 8.2 + 0.6 mmol/L, and the mean HgA1C was 8.1 + 0.7 and 6.7 + 1.1 at beginning and end of the study, respectively (p < 0.001). The mean body mass index (BMI) was 29.3 + 3.7 and 27.4 + 3.5 at the beginning and at the end of the study respectively (p < 0.001). There was no relationship between plasma metformin and lactate levels. The overall mean plasma lactate level across all blood samples was 1.48 + 0.5 and plasma samples > 2 mmol/L but < 3 mmol/L was found in 13.4% and 3–3.8 mmol/L in 2.7% plasma samples. None of our patients had lactic acidosis (levels > 5 mmol/L). Age > 65 and negative fluid balance were predictors for hyperlactemia.

Conclusion: Metformin may be used with caution in a particular group of ESRD who are on regular hemodialysis. Metformin allows better diabetic control with significant reduction of BMI.  The relationship between metformin and plasma lactate levels is lacking. HD may protect ESRD patients from metformin–associated lactic acidosis.