I would not worry about past use of Metacam. There is nothing you can do about it. Tramadol is a cheap, synthetic, opioid-type pain med. Too high a does makes a cat act spacey. Also, it makes many cats foam at the mouth right after administration. I am told it tastes terrible. If you have the pills/tablets/caplets, the standard does is 1/4 of a 50 mg tablet.