Improved Metabolic Control in Insulin-Dependent Diabetes Mellitus With Insulin and Tolazamide

• The influence of sulfonylurea drugs in enhancing the effect of endogenous insulin is well documented. Furthermore, combination therapy with sulfonylurea and insulin is effective in the treatment of type II diabetes mellitus. Therefore, to assess the efficacy of this type of combination therapy in type I diabetes, we conducted a double-blind clinical trial with tolazamide and insulin in 15 subjects with type I diabetes. The diagnosis of type I diabetes was confirmed by previous episodes of diabetic ketoacidosis and undetectable C-peptide levels in serum samples from blood drawn from patients two hours after breakfast. During the study protocol, placebo or tolazamide was randomly added to insulin and the combination therapy was continued for three months. In the placebo group, levels of fasting plasma glucose (FPG) and hemoglobin A 1c (HbA 1c ) did not alter significantly at the end of the study period. However, in the tolazamide group, levels of FPG and HbA 1c markedly improved after administration of tolazamide (FPG levels before therapy, 10.8±0.9 mmol/L [mean±SEM]; after therapy, 6.7±0.4 mmol/L; HbA 1c levels before therapy, 10.9%±0.6%; after therapy, 9.6%±0.5%). Therefore, adjuvant therapy with tolazamide and insulin may be beneficial in achieving adequate metabolic control in type I diabetes mellitus. ( Arch Intern Med 1988;148:1745-1749)