COADMINISTRATION OF ERYTHROMYCIN 500 MG 8H WITH A SINGLE DOSE OF CILOSTAZOL 100 MG INCREASED CILOSTAZOL C MAX BY 47% AND AUC BY 73%. OMEPRAZOLE, WARFARIN AND ASPIRIN HAD NO SIGNIFICANT EFFECT ON CILOSTAZOL WHEN CO-ADMINISTERED. DILTIAZEM, A MODERATE INHIBITOR OF CYP3A4, HAS BEEN SHOWN TO INCREASE CILOSTAZOL PLASMA CONCENTRATIONS BY APPROXIMATELY 53%. STRONG INHIBITORS OF CYP3A4, SUCH AS KETOCONAZOLE, ITRACONAZOLE, FLUCONAZOLE, MICONAZOLE, FLUVOXAMINE, FLUOXETINE, NEFAZODONE, AND SERTRALINE, HAVE NOT BEEN STUDIED IN COMBINATION WITH CILOSTAZOL BUT WOULD BE EXPECTED TO CAUSE A GREATER INCREASE IN PLASMA LEVELS OF CILOSTAZOL AND ITS METABOLITES THAN ERYTHROMYCIN.