Furosemide should not be administered with NSAIDS because they:
Indomethacin and other NSAIDs diminish the action of high ceiling diuretics. Inhibition of PG synthesis in the kidney, through which furosemide and related drugs induce intrarenal haemodynamic changes which secondarily affect salt output, appears to be the mechanism. Antihypertensive action of thiazides and furosemide is also diminished by NSAIDs.
Inhibit prostacyclin synthesis
Prevent platelet aggregation
Decrease sodium reabsorption
Increase the secretion of furosemide in urine