Synek P
Institutu pro dalsí vzdĕlávání lékarů a farmaceutů, Praha.
Cas Lek Cesk. 1991 Feb 1;130(5):148-51.
The molecular structure is one of the keypoints that govern both the extent of extracardiac action of cardiac glycosides and their different kinetics. The apolar, fat soluble digitoxin is very well absorbed from the intestine, its onset of action is slow, binds to a high degree to albumin and undergoes enterohepatic recirculation which accounts for a long elimination half time and stability of plasmatic levels. Digitoxin is largely excreted via gastrointestinal tract. The absorption of digoxin is less reliable, onset of action occurs earlier and the binding to albumin is considerably less than that of digitoxin. The drawback, however small, of digoxin lies in a lower stability of plasma levels and prevailing renal excretion. The molecule of strophatin is highly polar, its absorption from the intestine negligible and can be administered only intravenously. The onset of action is prompt, elimination half time short and about half the injected amount is excreted extrarenally.
分子结构是决定强心苷心脏外作用程度及其不同动力学的关键因素之一。非极性、脂溶性的洋地黄毒苷从肠道吸收良好，起效缓慢，与白蛋白高度结合，并经历肠肝循环，这导致其消除半衰期长且血浆水平稳定。洋地黄毒苷主要通过胃肠道排泄。地高辛的吸收不太可靠，起效较早，与白蛋白的结合远低于洋地黄毒苷。然而，地高辛的缺点在于血浆水平稳定性较低且主要经肾脏排泄，尽管这个缺点很小。毒毛花苷分子极性很强，从肠道吸收可忽略不计，只能静脉给药。起效迅速，消除半衰期短，约一半的注射量经肾外排泄。
