My spouse is having sore throat and mild fever. He just took two tablets of tylenol (acetaminophen) extra strength at one time. But fever rose up to 39.9c instead.?

Febrile illness. A fever of 39.9 c is quite high, but can happen with certain viral illnesses or other infections. Influenza is a common cause of high fever and sore throat at this time of year and fever can "break through" tylenol/acetaminophen. If fever persists or other symptoms develop, see your doctor! fever 2 hours after tylenol can often be controlled with 400 mg (2 otc tablets) of ibuprofen.