Effects of gliclazide--a new antidiabetic agent--on blood platelet function in vitro and in vivo.

Unlabelled: The effect of gliclazide on platelet activity was investigated and compared to that of tolbutamide and glipizide.

In Vitro Studies: adenosine diphosphate induced human platelet aggregation was inhibited by gliclazide in high concentrations (0.5--2.0 mg/ml). In the same concentration range tolbutamide exhibited a slightly less pronounced inhibitory effect. Collagininduced human platelet aggregation was inhibited by gliclazide, glipizide and tolbutamide in a concentration range of 0.5--2.0 mg/ml. Gliclazide had a similar effect on rabbit platelets. In vivo studies: Both acute and seven days administration of gliclazide to rabbits resulted in prolonged primary and total hemostatic plug formation time both in arterioles and venules. Similar results were obtained with tolbutamide and glipizide. Experiments with laser-induced platelet plug formation in the rabbit ear chamber demonstrated that 100 mg gliclazide/kg body weight and 25 mg gliclazide/kg body weight during 7 days significantly reduced the number of platelet emboli formed during 10 minutes after laser injury.