I'm so glad you ask this question. I hope someone answers. I have been taking tylenol #4 for about a year. It seems at times this medication makes the pain worse. I ask my doctor if this is possible, he just looked at me like I was crazy and said, NO. I don't think he really cares anyway. Last week when I went to see him he was running us in every 15mins. like clock work. I said, "your fast today", he said, "ya, as long as people don't have to talk".