Is metformin safe enough for ageing type 2 diabetic patients?

We assessed the effect of adding low doses of metformin to sulfonylurea therapy in 76 elderly Type 2 diabetic patients by monitoring glycaemic control and blood lactate for one year. Metformin markedly improved glycaemic control. Fasting lactate concentrations were not affected and post-meal lactate peaks were minimally increased. Additional benefits included an improvement in some lipid parameters, a reduction in serum uric acid and a significant weight loss in overweight patients. Metformin was clinically well-tolerated. Instead of advanced age alone, renal function and/or any other age-related factor likely to contribute to lactate overproduction should be the basis for deciding on metformin therapy. No evidence indicated that metformin should be denied "a priori" to ageing Type 2 diabetic patients.