CleanUP IPF for the Pulmonary Trials Cooperative

This is a randomized, un-blinded, phase III, multi-center clinical trial of an antimicrobial therapy strategy in idiopathic pulmonary fibrosis patients. Our overall hypothesis is that reducing harmful microbial impact with antimicrobial therapy will reduce the risk of non-elective, respiratory hospitalization or death in patients with Idiopathic Pulmonary Fibrosis (IPF). Subjects will be randomized 1:1 to either receive a prescription drug voucher for oral antimicrobial therapy in the form of one double strength 160 milligrams (mg) trimethoprim/800mg sulfamethoxazole (double strength co-trimoxazole) twice daily plus folic acid 5 mg daily OR doxycycline 100mg once daily if weight \< 50 kilograms (kg) or 100mg twice daily if weight \> 50 kg. Patients randomized to receive antimicrobial therapy will be given co-trimoxazole unless they have an allergy, contraindication to co-trimoxazole, renal insufficiency (glomerular filtration rate (GFR) \< 30 milliliters (ml)), are hyperkalemic (potassium \> 5 milliequivalents(mEq)/liter(L)), or are concomitantly taking an angiotensin converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), or potassium sparing diuretic in which case they will receive doxycycline. Participation in this study will be between 12 months and 36 months depending on time of enrollment.