Insulin and a sulfonylurea agent in non-insulin-dependent diabetes mellitus.

Using a double-blind crossover design, we studied the effect of tolazamide, an orally administered sulfonylurea, in 11 patients with non-insulin-dependent diabetes mellitus, poorly controlled on 40 units/day or more of insulin; all had previously failed to respond adequately to oral hypoglycemic agents and diet. In addition, six nondiabetic sex-, age-, and weight-matched controls were studied. Tolazamide significantly lowered fasting plasma glucose level from 272 +/- 21 to 222 +/- 31 mg/dL, increased fasting C peptide concentration from 0.09 +/- 0.03 to 0.28 +/- 0.10 pmole/mL (controls, 0.23 +/- 0.2 pmole/mL), and increased integrated C peptide concentration during a test meal (area under the curve) from 42 +/- 18 to 95 +/- 22 pmole/mL X min (controls, 94 +/- 8 pmole/mL X min). These data show that addition of tolazamide markedly increased fasting and meal-stimulated insulin secretion and modestly lowered fasting plasma glucose concentrations. We conclude that some patients who cannot achieve satisfactory control with oral hypoglycemic agents and diet may benefit from combined therapy with oral sulfonylurea agents plus insulin.