Gugler R, Eichelbaum M
Leber Magen Darm. 1981 Apr;11(2):81-7.
Disposition of drugs, which are primarily metabolized by the liver, will be influenced in chronic liver disease by the following factors: intrinsic clearance, liver blood flow, and shunt volume. This group of drugs may be divided in two subgroups: (a) drugs with a high clearance, a high extraction rate and a short biological half-time, and (b) drug with a low clearance, a low extraction rate, and a long biological half-time. A high extraction rate means a low systemic bioavailability, since a rather big proportion of the drug will be eliminated after oral intake already during the first pass through the liver (= first past effect). In liver cirrhosis bioavailability may be increased manifold because of the portosystemic shunting. Thus there is the danger of overdosage in group (a) drugs because of two mechanisms: reduced elimination and increased bioavailability.
主要经肝脏代谢的药物的处置，在慢性肝病中会受到以下因素影响：内在清除率、肝血流量和分流体积。这类药物可分为两个亚组：（a）清除率高、提取率高且生物半衰期短的药物，以及（b）清除率低、提取率低且生物半衰期长的药物。高提取率意味着全身生物利用度低，因为相当大比例的药物在口服后首次通过肝脏时就会被消除（即首过效应）。在肝硬化中，由于门体分流，生物利用度可能会成倍增加。因此，（a）组药物存在因两种机制导致过量用药的风险：消除减少和生物利用度增加。
