Furosemide is a loop diuretic

It interferes with the concentrating capacity of the loop of Henle.

It is effective in patients with renal dysfunction, whereas the thiazides are NOT.

It potentiates the nephrotoxic effects of cephalosporins and the ototoxic effects of aminoglycosides.

NSAIDs inhibit renal prostaglandin, causing sodium to be retained, which reduces the diuresis caused by furosemide.

Furosemide is a venous and arteriolar dilator and thus reduces both preload and afterload in a time frame just before the period of onset of a significant diuresis.