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Metolazone是一种比较长效且排钾作用较小的新的排钠利尿剂。它的许多药理学特性与噻嗪类利尿剂相似。口服后在胃肠道中极易吸收,但大剂量时,吸收不完全。口服后2～7小时血内达最高水平。从肾脏排出时游离而不代谢,因而其排尿作用大为增强。Metolazone主要由肾排出,但在一般治疗剂量下,有相当的量出现在粪便中。一次口服后于2～4日内排尽。Metolazone之代谢主要是羟化,然后氧化。 Metolazone在肾单位作用于皮质稀释段,阻滞钠之再吸收,引起明显的磷酸盐尿,但它对碳酸酐酶活力的抑制作用较弱。起初认为Metolazone对钾的排泄只有很小的作用。以后才证明可以发生尿高钾及低血钾,而且在某些病人中,钾的排泄超过钠和水的排泄。一般说来,
Metolazone is a new, long-acting, natriuretic diuretic that produces less potassium. Its many pharmacological properties are similar to those of thiazide diuretics. After oral administration in the gastrointestinal tract easily absorbed, but the high dose, the absorption is not complete. 2 to 7 hours after oral administration of the highest level of blood. Free from the kidneys without metabolism, so its role in urination greatly enhanced. Metolazone is mainly excreted by the kidneys, but at normal therapeutic doses, considerable amounts occur in the stool. After an oral drained within 2 to 4 days. Metolazone metabolism is mainly hydroxylation, and then oxidation. Metolazone acts on the cortical dilute segment in the nephron and blocks sodium reabsorption, causing significant phosphate urinary excretion, but it has weaker inhibitory effects on carbonic anhydrase activity. At first thought Metolazone only a small role in the excretion of potassium. Later proved that high urine potassium and hypokalemia can occur, and in some patients, potassium excretion exceeds sodium and water excretion. In general,