What is the maximum dose of vicodin that's safe per day?

Vicodin 5/500 max dose is 8 tablets/day. This is based on the acetaminophen portion of Vicodin (The maximum dose of acetaminophen is 4 g per day). Hydrocodone by itself does not have an established maximum dose. This doesn't mean that you can't overdose on it, it just means that each patient's response is different, some will begin to experience toxicity before others, some will need more to alleviate pain.