My yorkie ate a Tylenol arthritis pill that is 650mg and want to know if he is going
To be OK he is about 5lbs

Would you be concerned if a 5lb baby had consumed a 650mg Tylenol arthritis pill?

I don't know if your dogs liver can detox that much,or the effects of the drug on its heart.

Call the vet.

VET. As little as 150mg/kg can be deadly. And at about 2.2kg, that means anything higher than 340mg is dangerous.

3rd the vet notion. Tylenol is a big time no-no for animals. This can be deadly, please seek help from your vet.