Headaches from headache medication?

Q. I have a long history of tension headaches and usually get relief by taking acetaminophen. Lately, the medication relieves the headache, but then the pain returns later in the day. Can acetaminophen lose its effectiveness, or could it be something else?

A. Any headache that is new or worsening should be evaluated by your doctor. He or she will try to diagnose the cause of your headache by reviewing your medical history and performing a physical examination.