Well, first, you're not taking 500mg of Vicodin really. 500mg is the dose of Acetaminophen (Tylenol) in your pills. Vicodin (Lortab) is a mixture of that and Hydrocodone. If you took 500mg of Hydro... you'd be in lala land for quite a while, Morphine coma style. Your hydrocodone dose probably ranges between 2.5-10mg (most usually 5mg). It's perfectly safe to take 2 of those if you're having pain problems, just don't go for 3. The hydrocodone in Vicodin/Lortab isn't the problem, you can take the entire bottles worth of it. The problem is the Acetaminophen. Any more than 1000mg in one dose is not good for you at all. If it's mixed with Ibuprofen it would depend on the dose mixed with it (usually lower than ones mixed with Tylenol).