Voluntary self-poisoning with metformin and antiretroviral therapy drugs

Metformin is the first-line oral drug prescribed in type 2 diabetes. The main severe side effect of this drug is metformin associated lactic acidosis (MALA), which generally occurs accidentally and rarely in patients with renal failure. We present here a case of voluntary self-poisoning with metformin and antiretroviral therapy drugs. On admission, the patient showed lactic acidosis with a pH of 7.19 (normal ranges: 7.38-7.42) and lactates at 9.40 mmol/L (normal ranges: 0.50-2.20 mmol/L). Metformin and antiretroviral therapy intoxication was confirmed by detecting these drugs with high performance liquid chromatography coupled with diode array detector (HPLC-PDA) and a another HPLC with mass spectrometry (HPLC-MS) then by a metformin dosage at 814 mg/L (therapeutic ranges: 1-2 mg/L). During hospitalization, liver dysfunctionned, contributing to an altered lactate elimination. Therefore, lactic acidosis increased as the patient's state worsened. Therapeutics were inefficient, leading to patient's death 30 hours after presentation. This observation illustrates a rare case of voluntary intoxication with a high dose of metformin and its unusual association with antiretroviral therapy drugs, that could increase lactic acidosis and cause liver failure.