Metacam and renal failure in cat


 
I have a cat who was given Metacam oral suspension for pain and swelling after having a abscess cleaned on his paw. The dosage was 9 drops by mouth once daily for 4 days. A few days after that he went into renal failure. Creatinin levels and BUN levels through the roof. Impending cardiac failure. He was put on IV fluids, has recovered some, but worried about permanent damage. What is the protocol for a vet prescribing "off label" medication? Should there have been a release form? Should there have been level set's done on blood work to determine if he was at risk for taking NSAID's? Since there is not a licensed dosage for cats in the US it is hard to tell if he was overdosed, but appears to be when looking at the 2 drop loading dose, and 1 drop maintenance dosage for a dog. Any help would be appreciated.