Nitrofurantoin
"I have been on Macrobid for a urinary tract infection for 4 days and still do not have relief.  I have called my Doctor and he has now prescribed me a sulfa drug.  I have used the sulfa drug in the past and it works quick.  I am miserable on the Macrobid, exhausted, irritable, weepy, nauseous and a have a headache.   "