Cilostazol(OPC 13013; OPC 21) is a potent inhibitor of PDE3A, the isoform of PDE 3 in the cardiovascular system (IC50=0.2 uM).
IC50 Value: 0.2 uM
Target: PDE3A
in vitro: Cilostazol caused a concentration-dependent increase in the cAMP level in rabbit and human platelets with similar potency. Furthermore, cilostazol and milrinone were equally effective in inhibiting human platelet aggregation with a median inhibitory concentration (IC50) of 0.9 and 2 microM, respectively. In rabbit ventricular myocytes, however, cilostazol elevated cAMP levels to a significantly lesser extent (p < 0.05 vs. milrinone). Cilostazol inhibited SIPA dose-dependently in vitro. The IC50 value of cilostazol for inhibition of SIPA was 15 +/- 2.6 microM (m +/- SE, n=5), which was very similar to that (12.5 +/- 2.1 microM) for inhibition of ADP-induced platelet aggregation. Cilostazolpotentiates the inhibition of SIPA by PGE1 and enhances its ability to increase cAMP concentrations.
in vivo: A single oral adminstration of 100 mgcilostazol to healthy volunteers produced a significant inhibition of SIPA. Male C57BL/6J mice were assigned to five groups: mice fed a normal diet (groups 1 and 2); 0.1% or 0.3% cilostazol-containing diet (groups 3 and 4, respectively); and 0.125% clopidogrel-containing diet (group 5). Two weeks after feeding, groups 2-5 were intraperitoneally administered carbon tetrachloride (CCl4 ) twice a week for 6 weeks, while group 1 was treated with the vehicle alone.
Toxicity: Cilostazol in addition to dual antiplatelet therapy appears to be effective in reducing the risk of restenosis and repeat revascularization after PCI without any significant benefits for mortality or stent thrombosis.

PDE
Deltarasin
Diphylline
GSK256066
IBMX
Ibudilast
Milrinone
Mirodenafil
Nortadalafil
Oglemilast
Olprinone
PDE-9 inhibitor