I have been on SMZ-TMP for a UTI for about 9 days and I ended up in the emergency room last night for severe rash, and fever of 102. I have had the most horrible back pain, leg pain, cramping, joint pain, muscle weakness and migraine since I started taking it. I thought most of that was due to the UTI/kidney infection and didn't realize that I am allergic to it. I stopped taking it 24 hours ago, and while I still have a slight rash, headache, slight fever and body aches I feel a helluva lot better than I have in over a month. People need to be aware that the sulfur in this drug can cause serious problems.