Diurnal pattern of plasma insulin and blood glucose during glibenclamide and glipizide therapy in elderly diabetics.

The effect of a single and a split dose of glibenclamide and glipizide on the diurnal levels of blood glucose and plasma insulin were compared in 15 insulin-independent diabetics. The patients were treated for two weeks with a) glibenclamide or glipizide 5 mg b.i.d., b) diet alone, c) glibenclamide or glipizide 7.5 mg o.d., and d) crossing over of c). The patients were on isocaloric diet and the diurnal levels of blood glucose and plasma insulin were determined after each period. As compared to the diet, the single morning dose of both drugs reduced the blood glucose values to the same extent (p < 0.001) without any effect on corresponding insulin-levels. The single morning dose was sufficient to provide adequate blood glucose control for up to 24-hours. There was no further benefit of the (even greater) split doses. In accordance with the augmented physiologic insulin release in the morning, a single morning dose of sulfonylureas may be the preferable dosage regimen in the treatment of elderly insulin-independent diabetics of moderate degree.