Metformin-related lactic acidosis: Case report

Metformin-associated lactic acidosis treated successfully by peritoneal dialysis in a resource limited setting: case report

“…Metformin is a small 165 Da molecule with an oral availability of 55% and a distribution volume of 1-5 L/kg. The elimination half-life is 8-20 hours in individuals with normal renal function [5]. Despite the increasing use of metformin, the prevalence of MALA is uncommon; 0.03 cases per 1000 patient-years [2].…”

“…The pathophysiologic mechanisms of hypotension in MALA include negative inotropic effects and increased systemic vascular resistance with acidosis. Profound hypotension that is unresponsive to fluid therapy may require vasopressors [5]. The use of sodium bicarbonate is controversial and not fully validated in the clinical scenario of lactic acidosis and haemodynamic instability, regardless of the aetiology [5].…”

“…Despite its being generally safe, metformin may lead to a rare but life-threatening adverse reaction: metformin-associated lactic acidosis (MALA) [2]. MALA is defined as the presence of pH < 7.35, blood lactate >2.0 mmol/L and PaCO2 < 42 mmHg within the context of recent metformin exposure [3-5]. It is associated with a mortality rate of up to 50% [3, 6, 7].…”

“…The etiology of lactic acidosis is multifactorial and uncertain: inhibition of gluconeogenesis by reducing hepatic lactate uptake, inhibition of pyruvate dehydrogenase activity and mitochondrial-reducing agent transport leading to increased metabolism of pyruvate into lactate [3, 9]. It also impairs lactate clearance by the liver through the inhibition of complex 1 of the mitochondrial respiratory chain [5]. MALA usually occurs with impaired renal function but may occur with preserved renal function in the setting of massive metformin ingestion [3, 4].…”

“…MALA usually occurs with impaired renal function but may occur with preserved renal function in the setting of massive metformin ingestion [3, 4]. Voluntary poisoning is rare, and its characteristics and prognosis are seldom reported in the literature [5]. Intermittent haemodialysis is the most frequently reported treatment modality and early continuous renal replacement therapy (CRRT) has been suggested as an alternative along with supportive measures [3].…”