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 treatment of thrombotic disorders, such as chronic arterial obstruction, and is a vasodilator as well. In the present study, cilostazol was intravenously administered to seven anesthetized cats, and the optic nerve 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 microg/kg/min, although there were no significant changes in ONH and choroidal blood flows. When the drug was given at 0.1 microg/kg/min, ONH blood flow remained significantly higher than the baseline, 54+/-37% (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 was 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 administration of cilostazol increases both ONH and choroidal blood flows, suggesting the potential usefulness of cilostazol for both prophylactic and therapeutic management of ophthalmic circulatory disorders.