... Thanksgiving holiday weekend it was impossible to call my doctor to change the med. I told my husband that even though I hunted most of deer season with no problem, I was short of breath after the 4th day of Bactrim, he told me that I was getting old so I thought maybe I was comming down with a cold. I did not realize that it was a reaction to the medicine. I continued the 7 day supply because you should finish the medication until finished right? Maybe not. I called my doctor after the holiday and told him about the problem and that the UTI had not cleared up. He then prescribed me sufamethsole the generic form of Bactrim. I have not gotten over the shortness of breath and a very annoying cough. I smoked but I have not smoked for 20 years. I have always gotten over a cold easily and been quite healthy. I have gotten 2 colds since and I have a terrible bark to my cough when I get a cold. Is it possible to develop bronchitis and COPD after using Bactrim?