Potential interactions between cilostazol and probucol: A two-part, single-dose, open-label study in healthy Korean male volunteers

Combined therapy with cilostazol, an antiplatelet agent, and probucol, an antihyperlipidemic agent, has been reported to prevent restenosis after percutaneous transluminal coronary angioplasty. However, the potential for pharmacokinetic drug interactions between the 2 agents has not been evaluated.The aims of this study were to compare the pharmacokinetic properties of cilostazol and probucol administered alone and together in healthy Korean male volunteers.This open-label study in healthy adult (age 20-40 years) male volunteers consisted of 2 parts. Part A had a 1-sequence, 2-period crossover design in which each subject received cilostazol 100 mg (1 tablet) in period 1 and cilostazol 100 mg (1 tablet) plus probucol 500 mg (2 tablets) in period 2. Part B had a parallel-group design in which one group received probucol 250 mg (1 tablet) and the other received probucol 250 mg (1 tablet) and cilostazol 100 mg (1 tablet). Geometric mean ratios for C(max) and AUC were compared by ANOVA, and pharmacokinetic parameters were also compared by t tests. Tolerability was evaluated based on adverse events, ECGs, vital signs, and clinical laboratory test results.Twelve healthy volunteers completed part A; their mean age was 24.1 years (range, 21-29 years), mean height 171.8 cm (range, 163-177 cm), and mean weight 65.2 kg (range, 56.3-77.6 kg). Of the 20 healthy volunteers enrolled in part B, 19 completed the study; their mean age was 25.1 years (range, 21-34 years), mean height 173.2 cm (range, 162-183 cm), and mean weight 65.5 kg (54.0-78.0 kg). The pharmacokinetic parameters of cilostazol and probucol did not differ significantly when the 2 agents were administrated alone or together. In part A, the geometric mean ratios for C(max) and AUC(0-60h) between coadministration and single administration of cilostazol were 0.8882 (90% CI, 0.7873-1.002) and 1.013 (90% CI, 0.8643-1.188), respectively, for cilostazol; 0.8758 (90% CI, 0.7584-1.011) and 0.9785 (90% CI, 0.7600-1.260) for the OPC-13015 metabolite; and 0.8730 (90% CI, 0.7486-1.018) and 1.004 (90% CI, 0.8847-1.140) for the OPC-13213 metabolite. In part B, the geometric mean ratios for C(max) and AUC(0-648)h between coadministration and single administration of probucol were 1.134 (90% CI, 0.8177-1.572) and 1.070 (90% CI, 0.7364-1.555), respectively. Twenty-five adverse events were reported by 9 subjects in part A; the most frequently reported were headache (10 events) and nausea (4 events). Twenty adverse events were reported by 10 subjects in part B; the most frequently reported were headache (4 events) and productive cough (3 events). No clinically significant changes were noted in vital signs, ECGs, or laboratory values.In these healthy Korean male volunteers, coadministration of single doses of cilostazol and probucol had no significant effects on the pharmacokinetics of either drug. ClinicalTrials.gov identifier: NCT00549978.