what is macrobid used for
6 Reviews. 6 Reviews. Macrobid is the brand name for nitrofurantoin, an antibiotic used to treat or prevent urinary tract infections. Macrobid works by killing the bacteria that cause the infection or by preventing the bacteria from growing.The Food and Drug Administration (FDA) approved Macrobid, made by Proctor and Gamble Pharmaceuticals, in 1992.acrobid works by killing the bacteria that cause the infection or by preventing the bacteria from growing. The Food and Drug Administration (FDA) approved Macrobid, made by Proctor and Gamble Pharmaceuticals, in 1992.