Effectiveness of Metformin on Poorly Controlled Insulin-Treated Diabetes Mellitus

A new way of administrating metformin has been reviewed for the treatment of diabetic patients suffering from obesity and insulin resistance.We studied the effectiveness of the combined administration of metformin and insulin in diabetic patients who were severely or slightly obese. These patients were selected from a group of inpatients and outpatients at Tokyo Metropolitan Futyu Hospital during the period from April 1999 to January 2001. We included 37 patients who were obese and who possibly demonstrated insulin resistance, and who also had problems controlling their blood glucose level despite insulin treatment. Patients were excluded if they were diagnosed to have either a hepatic or renal dysfunction or either cardiovascular or any circulatory disorders since they are risk factors for lactic acidosis after the administration of metformin.After evaluation of the results of the combined administration of metformin and insulin, and also controlling the blood glucose level, and by varying the dosages of insulin, an improvement in the control of the blood glucose level was observed in 30 patients, and a reduction in the dosage of insulin was observed in 11 patients. No side effects which required a discontinuation of medications were discovered during the study period.The previously reported administration ranged from 850-2, 500mg/day in the U.S. and Europe. In addition to the combination use of 500mg-750mg/day of metformin with insulin was also found to be effective. Based on these results, we believe that further clinical studies with a larger number of patients are called for to evaluate the optimal administration dosage of metformin.