METFORMIN-ASSOCIATED LACTIC-ACIDOSIS IN SWEDEN 1977-1991

Since the withdrawal of phenformin in 1978, the use of metformin has i ncreased from 13,500 to 22,00 patient years/year. During the period 19 77-91 a total of 18 cases of metformin-associated acidosis was reporte d, of which 16 had lactic acidosis. The incidence of reported acidosis and lactic acidosis decreased from 1.50 cases per 10,000 patient year s in 1977-81 to 0.24 cases per 10,000 patient years 1987-91, probably due to lower doses doses and reduced usage in the very old. All the re ports described patients with several other concomitant diseases, main ly cardiovascular and renal, when the acidosis was diagnosed. It is im portant continuously to re-evaluate metformin therapy and to stop trea tment at the onset of impaired renal or cardiovascular function.