We stopped the metcam after we noticed our cat Sissy acting lethargic and looking wobbly when she walks. She now has lost her appetite and has not had a bowel movement in days. Before she went to the vet for slight bleeding from the rectum, and given an  injection of metacam, she was playful, and with a healthy appetite.  Only two days of drops of  metacam and she now sleeps all day, doesn't eat or use the litter box except for urine. No more metacam, going to an emergency today for this problem