I've been on MTX for just two weeks, a very low dose. Last Wednesday I developed a massive cold. In addition to the stuffed nose, I've been light headed off and on, and today have developed a productive cough. Now, one of the side effects of MTX is a serious pulmonary condition, and my rheumy I saw a week ago said that I should be in touch if I get a cough. But surely the cough is from the cold. While I know MTX is suppressing my immune system, could it have started working so fast? Before this I never got colds. Should I be worried about pneumonia? I do not have a fever. Here it is Saturday, and I have no desire to go to the ER. What do you think? Should I call the doctor? I assume it would be to a service. I own a gallery and business has been terrible (I am in Michigan, enough said) and I need to work today. keep an eye on things, but as long as you aren't running a fever and the cough doesn't worsen then you can probably wait and see how you feel on Monday....