LACTIC ACIDOSIS IN PHENFORMIN‐TREATED DIABETICS

Abstract

Abstract From a fairly large clinical material of diabetics treated with the antidiabetic drug phenformin 21 patients showed clinical and laboratory evidence of lactic acidosis. The diagnosis was confirmed by direct and specific determinations of lactate (L) and pyruvate (P) in 15 of the patients. All of them showed raised L and P levels with a raised L/P ratio. All remaining six patients had severe metabolic acidosis with low pH values and increased so called “anion gap”. Predisposing factors in patients developing lactic acidosis on phenformin treatment seem to be impaired renal and liver function, in some cases also alcohol consumption and interaction with other drugs. The mortality rate is high despite intensive treatment, in the present material 33%. It is concluded that phenformin therapy is contraindicated in diabetics with impaired renal or liver function. The treatment dose also seems to be of importance. The prognosis depends on early diagnosis and intensive treatment with bicarbonate intravenously, probably also in combination with administration of insulin and glucose. The exact role of phenformin in causing lactic acidosis is not known, but probable mechanisms are discussed.