I never could tolerate Cialis or Levitra(severe headaches) but I read a post(can't remember where) and the guy who posted found that if he drank two large glasses of water with the pill and took an aspirin(or Tylenol), little or no headache. Tried it this morning. 5 mg. Some flushing, warm feeling, nasal congestion...and just a barely there headache which disappeared after 2 hours, along with nasal congestion. Encouraged, now, to increase to 10 mg. I've read many positive posts on rxlist from men in their 60's, 70's and 80's who found Levitra to be the most effective with few sides. I'm 70 and still focused on restoring my erections, along with t shots.