Title:Metformin Toxicity: A Report of 204 Cases from Iran.
Volume: 8
Issue: 4
Author(s): Shahin Shadnia, Farnaz Barzi, Anvar Askari, Hossein Hassanian-Moghaddam, Nasim Zamani and Kimia Ebrahimian
Affiliation:
Keywords:
Hemodialysis, hypoglycemia, lactic acidosis, metformin, outcome, poisoning.
Abstract: Objective: The aim of this study was to evaluate the frequency of metformin-associated lactic acidosis in our
metformin-intoxicated patients, the general approach for their management, and determine the frequency of hypoglycemia
and outcome in these patients. We also wanted to see if there was a significant difference in the course and outcome of
metformin poisoning between our patients and those reported in the literature.
Materials and Methods: Files of all patients diagnosed with metformin toxicity were retrospectively evaluated. A purposemade
questionnaire containing the patients’ demographic data, vital signs and lab tests on presentation, time of
development of hypoglycemia and metabolic acidosis (if any), treatment modalities performed for the patients and their
indications, and the patients’ outcomes was filled. The patients were evaluated in total and then assigned into two groups
of metformin alone (group 1) and multi-drug toxicity including metformin (group 2) and were compared.
Results: A total of 204 patients were reviewed. Fifty-five (26.9%) were in group 1 and 149 (73.1%) were in group 2.
Sixteen and 52 patients in groups 1 and 2 had acidosis. Dialysis was performed in only four patients, all of whom
belonged to group 1 (P = 0.005). They were all dialyzed only once. Two patients (1%) died both of whom were in group
2. Groups 1 and 2 were insignificantly different in all characteristics except for their aspartate transaminase and creatine
phosphokinase. Almost 23% of the patients in group 1 had experienced hypoglycemia sometime during their course of
hospitalization.
Conclusions: Although lactic acidosis is considered to be a serious condition resulting in high mortality and morbidity
rates, it seems that our patients can easily and safely be managed with conservative therapies. Most of them do not need
aggressive treatments including hemodialysis. Metformin seems to cause hypoglycemia more than what was previously
considered.
