Why furesemide called high ceiling diuretics?
This is my interpretation of the ceiling dose of furosemide. Furosemide’s avalability in the body, when taken orally, varies greatly, from 30-90%; this is apparently considered a low bioavailability, as far as loop diuretics go. Diuretics must acheive what is called a threshold concentration to have a therapeutic effect (ie, to start working). Increasing the dose above the threshold will ellicit a dose-dependant increase in diuresis (what diuretics are supposed to do), until they reach a point where the maximum effectiveness they are going to have is reached. This is called the ceiling dose. So, if you go above the ceiling dose, no extra effects will be achieved. The ceiling dose of furosemide is 60-80mg, which, I am assuming, is pretty high compared to other diuretics in the same class.
