My cat Ebony hurt herself when outside on saturday and wouldn't put any wieght on her foot at all....... So I waited it out a couple days through the weekend and then on Monday called and spoke to my vet.  Took her into see him Tuesday because it wasn't any better.......  He did xrays and examined her and kept her over night for observation.  All I was told over the phone is that he wanted to keep her over night becasue he gave her some meds and wanted to watch her through the night but we can get her Wednesday after 10 am.  So we did.  My husband brought her home with the med that he gave to her.  The does at the vets was the injection but he sent home orally Metacam for her... I was told to give it to her everyother day for a week.  However I wanted to see what it is b4 I gave her any of it and ran into your site.  As of now she has had what the vet gave to her and seems to be doing great.  Walking on her leg now.  Not prefectly yet but LOTS better.  However I will not give her any more of this med after reading what I have read!  Not worth it..... She will heal without it and it isn't worth it to give her more.  But I just now pray that the amount he gave to her is ok and she will do ok with it.  Over 24 hours since the injection of it was givin to her.....  I think she was only givin one!!!  I pray!!!  That is all I was told about.......  But what was brought home I will not use! 
All of the stories I have read have said that they continued to give it to their cat or they had more then one dose of it one way or the other and most were a few or more doses.  So I guess ONE injection dose could be a good thing ONLY ONE if you trust your vet but DO NOT GIVE it orally at home to your cat.  Sounds like MORE then ONE dose is when everyone is seeing problems starting. 
I will not allow this to be givin to my cat again but I just doing want anyone whos cat had ONE dose to freak out~  Just watch them closly and DO NOT give more then that to your cat!!!!!!!  I wish he wouldn't have givin it to her now but it is over with!  So now I am hopeing that she will be ok!  So far looks great and seemed to help!  But like I said b4~  I WILL NOT give the orally med of Metacam he sent her home with to her~  NOT WORTH IT to me~  So please pray that the one dose she had is ok and she will be ok from it and I am so sorry to everyone that has lost a pet to this drug and I would not give it to your cat if you see this in time like I hope I did b4 anything happens~ 
Thank you for making everyone aware~
( I sure hope I seen this in time!  I will update you if anything changes for the worse with Ebony from the one dose she had.)