I have a chest infection and was prescribed a 5 day course of 500 mg Penicillin. I'm still coughing and just wondering if I should have stopped my Sulfasalazine? Does it stop the effects of the antibiotic? I was surprised I was only given a 5 day course too. What do other people do in this situation? I think I've read that you should stop Methotrexate while on antibiotics, so is it the same for Sulfasalazine ?