Iwamoto Toshihiko, Kin Kyoko, Miyazaki Kaori, Shin Kouichi, Takasaki Masaru
Department of Geriatric Medicine, Tokyo Medical University Hospital, Tokyo, Japan.
J Atheroscler Thromb. 2003;10(6):348-54. doi: 10.5551/jat.10.348.
To clarify the recovery of platelet function after abrupt withdrawal of cilostazol, we studied platelet function and cilostazol concentration in elderly who received cilostazol, 100 mg twice a day (200 mg/day), for a long period. After interviewing the time of final cilostazol intake, platelet aggregability was determined with an aggregometer using four different concentrations of adenosine-5'-diphosphate as an inducer, which showed the grading curve (GC) type and platetet aggregatory threshold index (PATI). Serum cilostazol concentration was also determined by high-performance liquid chromatography. The GC type and PATI showed suppressed platelet function until 15 hours after withdrawal in half of patients. Bleeding time measured by the Simplate method was prolonged within 4 hours, but recovered by 12 hours after the withdrawal. Some serum cilostazol concentrations were still high 15 hours after withdrawal, while platelets were inhibited even in patients with low serum concentration of cilostazol. In the group receiving the drug for less than 6 months, PATI correlated with serum cilostazol concentration, but platelets in the long-term administration group (more than 48 months) were suppressed at the low serum cilostazol concentration. These findings indicated that platelet function recovered within 12-16 hours after withdrawal in these patients.
为明确突然停用西洛他唑后血小板功能的恢复情况，我们对长期每日两次服用西洛他唑100mg（200mg/天）的老年患者的血小板功能和西洛他唑浓度进行了研究。在询问末次服用西洛他唑的时间后，使用聚集仪以四种不同浓度的5'-二磷酸腺苷作为诱导剂测定血小板聚集性，得出分级曲线（GC）类型和血小板聚集阈值指数（PATI）。血清西洛他唑浓度也通过高效液相色谱法测定。半数患者的GC类型和PATI显示，停药后15小时内血小板功能受到抑制。用Simplate法测定的出血时间在停药后4小时内延长，但在停药后12小时恢复。停药15小时后，部分患者血清西洛他唑浓度仍较高，而即使在血清西洛他唑浓度较低的患者中，血小板也受到抑制。在服药时间少于6个月的组中，PATI与血清西洛他唑浓度相关，但在长期给药组（超过48个月）中，低血清西洛他唑浓度时血小板仍受到抑制。这些发现表明，这些患者停药后12 - 16小时内血小板功能恢复。
