Nitrofurantoin
"I was diagnosed with a bladder infection and had been given the script for Macrobid. Right after taking the first pill I had the worst headache that NOTHING would help. I did take a 2nd pill and that about put me down with the headache. I took Advil, Tylenol. I ended up taking a Tramadol which helped a little. I felt very weak, out of sorts, nausea, NO appetite, gassy stomach and my neck hurt like crazy. Over all I felt like I had a real bad case of the flu. I also want to mention that I had extreme anxiety. I am already OCD and this medication magnified everything. I would rather suffer from the bladder infection than go through this again. I thought Bactrim was bad. The ONLY thing Macrobid helped with was my low grade fever."