Abstract
The therapeutic benefits of sulfonylurea in the treatment of diabetes were evaluated by 1) additional administration of glibenclamide for 48 weeks to patients receiving insulin alone, and 2) withdrawal of glibenclamide from the patients who had been treated with insulin and glibenclamide for 8 weeks. In the first part of the study, the addition of glibenclamide (8.8±0.6 mg/day) had no effect on plasma glucose (PG) and HbA1 in 6 patients (52±6 years old, 2 men and 4 women) without detectable plasma CPR. In 17 patients (61±2 years old, 10 men and 7 women) with measurable plasma CPR, 2-hr postprandial PG and HbA1 were significantly reduced by addition of glibenclamide (9.4±0.3 mg/day)(PG: 310±23 vs 260±16 mg/dl, HbA1: 10.4±0.3 vs 9.6±0.3%). Plasma CPR was significantly increased in this group at 24 weeks (2.4±0.3 to 3.2±0.3 ng/ml) but returned toward the baseline at 48 weeks 2.8±0.5 ng/ml). In the second part of the study, 2 weeks after the withdrawal of glibenclamide (9.1±0.5 mg/day), fasting and postprandial PG were significantly increased (fasting: 131±21 to 223±36 mg/dl, postprandial: 219±11 to 305±41 mg/dl) with decrease in plasma CPR (fasting: 1.8±0.3 to 1.4±0.1 ng/ml, postprandial: 3.8±0.4 to 2.9±0.4 ng/ml).
Glibenclamide improves glycemic control primarily by enhancing insulin secretion, and insulin/glibenclamide therapy is beneficial for diabetics retaining insulin secretion.
