I was diagnosed on Thursday evening, after a CT scan with a severe Sinus infection. I have had dreadful headaches for a while, but no other symptoms. As I am allergic to quite a number of medications, I was given Clarithromycin 500. I have had ulcers, but they don't bother me at all, but I did feel dreadful about 2-3 hours after taking the medication. I have had my afternoon dose, but I have a dreadful headache, is is okay to take tylenol ? to alieve the pain?