What usually causes acute kidney failure in the elderly?

Meds and Dehydration: Acute kidney failure occurs predominantly from newly prescribed medications like a diuretic (hctz (hydrochlorothiazide) or lasix) or from certain anti-hypertensive medications like an ace or arb (enalapril or cozaar). Also akf occurs in the elderly if they do not get enough water intake especially in warm environments when they sweat a lot.