Clinical presentation

Most of the clinical effects of metformin poisoning are related to increased lactate production. Metformin poisoning does not cause hypoglycaemia.

Effects of metformin poisoning include:

• metabolic effects—hyperlactataemia and metabolic acidosis, hyperkalaemia
• gastrointestinal effects—nausea, vomiting, abdominal pain
• cardiovascular effects—hypotension and tachycardia due to metabolic acidosis or dehydration; may progress to cardiogenic shock
• central nervous system effects—sedation, coma and seizures secondary to acidosis
• multiorgan dysfunction—especially acute kidney and liver dysfunction; can progress to multiorgan failure.