Abstract
Equipotent doses of the sulfonylurea drugs tolbutamide, glibornuride, and glibenclamide
were determined for normal persons and for dogs by means of a maximum blood glucose
reduction of 30% or 23%, respectively, as a criterion of drug potency. In individuals
and experimental animals the hypoglycemic effects of different sulfonylurea drugs
in equipotent doses were identical with respect to the maximum percent blood glucose
reduction, as well as to the integrated area of the percent decrease of blood glucose.
The difference observed between the sulfonylurea compounds described, concerned their
insulin-stimulating effects. Thus, tolbutamide induced a lower peripheral insulin
level than glibenclamide to obtain the same blood glucose decrease. Glibornuride and
tolbutamide had similar effects. In individuals and experimental animals, the ratios
of the integrated areas of blood glucose reduction/insulin increase were identical
for each of the sulfonylurea drugs, in spite of the differences between blood glucose
reduction and insulin increase. There were marked variations, however, between the
different sulfonylurea drugs, in special with regard to the time periods at which
maximum increments in insulin secretion were established: the rapidly exhibited insulin
secretion in response to both tolbutamide and glibornuride on the one hand and the
delay in the insulin secretion following glibenclamide.
Key words
Tolbutamide - Glibornuride - Glibenclamide - Equipotent Doses - Integral of Blood
Glucose Decrease - Integral of Insulin Increase - Extrapancreatic Effects
