Son, 27, taking augmentin, gave him advil at 6:00 pm, can i safely switch to tylenol (acetaminophen) at 3:00 am, 9 hours later?

Absolutely: Ibuprofen (advil) can safely be given every 6 hours and Acetaminophen (tylenol (acetaminophen)) every 4 hours. They actually can be used together as there is no interaction and one is metabolized by the kidney, the other the liver. Remember, no more than 3000mg per 24 hours for tylenol (acetaminophen) for adults. Augmentin makes no difference in use of either med.