title: Phase I study of cilostazol. Safety evaluation at increasing single doses in healthy volunteers.
abstract: The safety and blood concentrations of the novel synthetic platelet aggregation inhibitor cilostazol (6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)-qui nolinone, OPC-13013) were determined in eight healthy volunteers. The drug was orally administered to the subjects once at successive dose increments of 25, 50, 75, 100, 150, 200 and 300 mg/body. Subjective complaints were headache at 75 mg/body in 1 of 4 subjects and dull headache at 75 mg/body in 2 of 4. Each of these symptoms was also seen at higher doses in 1 to 2 of 4 subjects. Clinical laboratory values, blood pressure and heart rate were normal. Blood concentrations of the drug peaked after 3 to 4 h, the levels declining with half-lives of 2.6 to 3.2 h in the alpha-phase and 19.5 to 25.5 h in the beta-phase. The decline was generally prompt. The average peak concentrations were 283.7, 663.4, 540, 823.6, 1110.4, 1129.2 and 1623.9 mg/ml at the above doses, respectively. The effect of food on the blood concentration was also studied; however, the areas under the curve did not indicate significant differences between the fed and fasted subjects.
mesh_terms: D000328:Adult; D001393:Azoles / Q000633:toxicity*; D001774:Blood Chemical Analysis; D001794:Blood Pressure / Q000187:drug effects; D000077407:Cilostazol; D004334:Drug Administration Schedule; D004341:Drug Evaluation; D004562:Electrocardiography; D005343:Fibrinolytic Agents / Q000378:metabolism / Q000633:toxicity*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D013777:Tetrazoles / Q000378:metabolism / Q000633:toxicity*; D014665:Vasodilator Agents / Q000378:metabolism / Q000633:toxicity*
chemical_list: D001393:Azoles; D005343:Fibrinolytic Agents; D013777:Tetrazoles; D014665:Vasodilator Agents; D000077407:Cilostazol