urinary tract infection
"This drug put me in the ER last night. I've had UTIs before and have taken cipro, etc, without issue, but yesterday I was prescribed Nitrofurantoin for the first time.  Approximately two hours after taking it, I felt like I was going to throw up, and shortly thereafter, I became severely winded after climbing just one flight of stairs. I sat on the floor trying to breathe for almost a full hour and just couldn't catch my breath. Then, I began shaking uncontrollably and was told I needed to go to the ER as they thought my windpipe was inflamed and closing up. I arrived to the hospital visibly shaking, my fever shot up, and I spent several hours being monitored and given pills to counter-act the Nitro before they let me leave.  Terrifying."