比较lmwh的药物动力学。

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Samama MM, Gerotziafas GT

比较lmwh的药物动力学。

Semin Thromb Hemost。2000; 26增刊1:31-8。

PubMed ID
11011804 (在PubMed
]
文摘

各种制剂的低分子量肝素(lmwh)是可用的。他们属于同一家庭compounds-ie,肝素衍生品窄分布的平均分子量(多工作站系统)。lmwh有不同的制备方法,这导致的变化意味着MW,兆瓦的分布、药代动力学(PK)和药效学(PD)配置文件。这些化合物的平均兆瓦范围从3600 - 6500道尔顿。anti-Xa的比率(aXa)和anti-IIa (aIIa)不同lmwh的活动范围从1.5 > 10。后皮下注射(SC)的预防或治疗剂量,等离子安盛的高峰值或aIIa活动可能两倍三倍,因为生物利用度的差异,不同等离子体间隙(Clplasma)和半衰期(t1/2)。注射等量的产品,基于安盛和aIIa国际单位(IU),可能导致不同区域曲线下的各自活动。虽然tinzaparin aIIa高特定活动每毫克(因此,低安盛/ aIIa比率),SC注入40毫克的伊诺肝素(4000安盛国际单位)导致更高的安盛峰值在全髋关节置换患者超过4500 tinzaparin安盛国际单位。aIIa和安盛峰值的差异活动是使用高剂量lmwh时更加引人注目。激活局部血栓形成质时间(aPTT)可以显著延长,影响aIIa和安盛活动有关。 The volume of distribution of LMWHs is of the same order of magnitude as that of the plasma volume. The mean retention time of aXa activity varies from 5.2 (dalteparin) to approximately 7 h (enoxaparin, nadroparin). Bioavailability of prophylactic doses of LMWHs ranges from 86% (dalteparin) to 98% (enoxaparin, nadroparin). PK parameters appear to be minimally affected by a patient's age. The Clplasma is different for each LMWH: 16 mL/min enoxaparin, 21 mL/min nadroparin, 33 mL/min dalteparin, 19 mL/min reviparin, and 22 mL/min tinzaparin. Accumulation of product has been observed for almost all LMWHs in patients with renal insufficiency. LMWHs are effective and safe for treatment or prophylaxis of venous thromboembolism during pregnancy, because they do not cross the placenta. No data are available regarding the passage of LMWHs into the milk in lactating women. Although LMWHs are also effective in prevention and treatment of thromboembolic disease in children, optimal use of these agents in pediatric patients has not been determined. In summary, the PD and PK of LMWHs have been well documented and have demonstrated that LMWHs have a more predictable response, a greater bioavailability, and a longer aXa t1/2 than unfractionated heparin. However, their distribution of MW affects their physicochemical and biological properties, as well as PK characteristics. The concept of aXa/aIIa ratio (determined in vitro) does not account for the differing PK of aXa and aIIIa activity in circulating blood.

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