How can nsaids cause renal failure?

Prostaglandins. Nsaids inhibit prostaglandins, the bad ones that cause inflammation but also the good ones that help make your stomach coating and help maintain good blood flow in the kidneys. Over time, chronic NSAID use can cause kidney failure.
NSAIDS. They can reduce blood flow through the kidneys and they can cause inflammation within the kidney. Here's a good place to find out more: http://www.Uptodate.Com/contents/nsaids-acute-kidney-injury-acute-renal-failure-and-nephrotic-syndrome.