EFFECTS OF INTRAVENOUS CILOSTAZOL ON OPTIC-NERVE HEAD AND CHOROIDAL BLOOD-FLOW IN ANESTHETIZED CATS

Cilostazol is one of a number of anti-platelet agents used for the tre atment of thrombotic disorders, such as chronic arterial obstruction, and is a vasodilator as well. In the present study, cilostazol was int ravenously administered to seven anesthetized cats, and the optic nerv e head (ONH) and choroidal blood flows were continuously monitored in a noninvasive method using laser Doppler flowmetry. The systemic blood pressure dropped significantly by 4 +/- 4% (p<0.05) with cilostazol 0 .03 mu g/kg/min, although there were no significant changes in ONH and choroidal blood flows. When the drug was given at 0.1 mu g/kg/min, ON H blood flow remained significantly higher than the baseline, 54 +/- 3 7% (p<0.05) at maximum, immediately after the start of administration. Soon after the start of the infusion, a significant decrease, 17 +/- 10% (p<0.05) at maximum, in choroidal blood flow occurred, but this wa s followed by a significant increase, 35 +/- 27% (p<0.05) at maximum. At that time, the systemic blood pressure dropped significantly by 14 +/- 6% (p<0.05). These findings indicate that an intravenous administr ation of cilostazol increases both ONH and choroidal blood flows, sugg esting the potential usefulness of cilostazol for both prophylactic an d therapeutic management of ophthalmic circulatory disorders.