Lasix is the brand name for furosemide. It is a diuretic. If I had a nickel for every dose of furosemide I had ever given in my career as a critical care nurse I would be a very wealthy woman right now!
Furosemide is a "loop diuretic," which means that it is a diuretic that works on the ascending loop of Henle, part of the basic functional unit of the kidney.
A diuretic is a medication that causes the kidneys to excrete fluid.
Furosemide has many uses, but generally it is most commonly used for conditions which cause fluid retention due to inadequate pumping action of the heart which causes fluid to back up in the heart and body (congestive heart failure), and in kidney disease. Furosemide, along with other medications is also used to treat high blood pressure.
Furosemide is easier on the kidneys than some other diuretics that work a little differently, but one of the side effects of furosemide is that it causes a depletion of potassium along with excess fluid.
So, when we give furosemide we need to monitor blood potassium levels and supplement as needed to keep the potassium level at a level that is safe - low potassium levels can be life-threatening.
Furosemide has been around a long time - since the 1960's.