Older Cat Behavior

Question
Our cat just turned 15 and he recently was diagnosed with a kidney infection.  He has been on antibiotics and seems to be increasing his weight and acting more normal. He was using the litterbox until recently where he uses it right outside which I understand is due to him associating pain with urinating in the litterbox thus he is going outside instead.  He has also urinated on our bed a few times so we added a second litter box close by which has seemed to help.  

My main concern now is his behavior in general.  He tends now to sit on the bathroom sink counter and although he seems to want water at times he just sits there.  Most times face towards the wall.  We have also found him behind the door, face in the corner.  I know he doesn't feel well but he is really acting odd.

Answer
Mare,

Have you considered the possibility that your cat is blind? Sometimes you don't realize it because the cat acts the same. At 15 your cat is approximately 76 years old in human years and he is at the age where normal functions will start giving out. At the next vet visit I would have the vet check his eyesight.

Also the medication the cat is on may be making him act in that manner. I would give your vet's receptionist a call and see what the possible side affects are, or what the cat's reactions to it may be.

Tabbi