I just brought my 2 year old cat Tanner home in a box. I know he was given 2/ 0.27ml  (3 weeks apart) doses of Metacom for a injury due a cat fight.
He was so young and I so ignorant. I am heart broken. I do not have hard evidence to prove this caused his death, but he had the symptoms your web site described. 
I will call the manufacturer of Metacam and tell them my experience. I do not know if this will help someone else. I will tell all my cat lover friends to be aware this can kill. 
In Loving Memory of Tanner