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The treatment of hemodialysis, especially continous hemodialysis, might be beneficial to treat the patients with metformin toxicity.
Key words: Metformin Toxicity, Dialysis, Lactic acidosis
Introduction: Metformin is an oral anti-diabetic drug, which is a biguanide used to treat Diabetes Mellitus(1). Biguanides can be used as a monotherapy or combination with other drugs. Metformin increases the sensitivity of insulin, decreases the output of glucose from the liver, and increases the uptake of glucose by muscles(2). Common side effects are gastrointestinal such as metallic taste, bloating, abdominal discomfort, nausea, mild anorexia, and diarrhea(2). And one of the major side effects of metformin is lactic acidosis(3).
Case : A 26-year-old young patient after digesting 60 g metformin plus 900 mg pioglitazone for the suicidal purpose was admitted to the emergency ward. He presented with abdominal pain and discomfort, nausea, agitation, confusion, and lethargy 3 hours after digestion of drugs. His vital signs were as follows: blood pressure:115/85, pulse:110 beat/min, respiratory rate: 18 RR/min, oxygen saturation in room air: 96%. His laboratory results were glucose:123 mg/dL, creatinine:1,75 mg/dL, urea:27 mg/dL, alanine transferase(ALT):29 U/L, aspartate transferase(AST):17 U/L. Arterial blood gas (ABG) analysis showed acidosis pH:7.15, which was caused by elevated lactate levels. The lactate level was 7,8 mmol/L. The anion gap was calculated at 11 mmol/L(6 hours after the suicide attempt)(Table 1). The patient was transferred to the intensive care unit(ICU). At the time of admission to ICU, confusion, and lethargy worsened and blood glucose levels lowered to 64 mg/dL. IV dextrose (1 g/kg) was administered. IV saline was administered due to polyuria. A central venous catheter was performed and continuous dialysis was initiated. Hemodialysis was performed with Fresenius 4008 S device, 1.5 m2 high-flux FX-60 membrane (Fresenius), 300 ml/min blood flow rate, 500 mL/min dialysis fluid rate, 32 mmol/L bicarbonate, without ultrafiltration. At the 4th hour of dialysis, the patient was more oriented and cooperated. Continous dialysis was performed for 15 hours. Lactate levels lowered and at the 48th hours following admission to ICU, lactate levels were completely normalized. The patient was discharged 3 days after admission to the hospital.
Table 1: The results of ABG