I recently spent 10 days in ICU on a ventilator due to Methotrexate Pneumonitis, a serious complication of MTX. I was diagnosed with pneumonia & every doctor got it wrong, was 1 day from being unplugged when student doc found the link, given massive steroid dose & recovered! I'm upset that my Rheumy never told me about this. I've had severe RA for 1 year, inject 25mg Mtx weekly & have been on several other DMARDS. My new specialist says I can never receive a biological because of my severe reaction. My only. Drug now is prednisone & I'm not well controlled. Please be careful with. Methotrexate, it can be lethal to your lungs!!!!!