Multicenter case series of pediatric metformin ingestion.

Objective: There are no large studies, case series, or case reports of metformin ingestion in children. This study summarizes the clinical course and outcomes of metformin ingestion in children reported to the American Association of Poison Control Centers-certified regional poison centers.

Methods: This was a case series of all metformin ingestions in patients <18 years of age reported to eight regional poison centers. Data collection included age, gender, dose ingested, co-ingestants, symptoms, vital signs, laboratory values, length of hospital stay, and medical outcome. Entrance into the study required at least 24 hours of follow-up.

Results: Fifty-five cases were collected. Ages ranged from 15 months to 17 years, with a mean (+/- SD) of 42+/-4.4 years. The dose ingested, by history, ranged from 250 mg to 16.5 g, with a mean and median of 1710+/-3391 and 500 mg, respectively. Forty-one children (76%) ingested a maximum of two tablets (< or =1700 mg). In the children younger than six years, dosage ranged from 9 to 196 mg/kg, with a mean and median of 60+/-41.1 and 40 mg/kg, respectively. Thirty-seven children were evaluated in a healthcare facility. Clinical effects were limited to nausea (2), diarrhea (2), and dizziness (1). None of the 38 children who had serial glucose measurements experienced hypoglycemia. Arterial blood gas and electrolyte measurements were performed in three and 19 children, respectively. No evidence of acidosis was demonstrated. Two children had lactate concentrations measured and were determined to be in the normal range. Twenty-nine patients received activated charcoal. Five patients received parenteral glucose and one adolescent with a history of diabetes received insulin for hyperglycemia.

Conclusions: Unintentional ingestion of < or =1700 mg of metformin in the healthy pediatric population does not appear to pose a significant health risk of hypoglycemia or detrimental outcome. In the 21 children who were tested for either blood glucose, electrolyte, or lactate concentrations, no evidence of lactic acidosis was seen.