rn Please consult your physician before taking any medication. Macrodantin generic 100mg 40 Caps Generic Name: nitrofurantoin (oral) (NYE troe fue RAN toin) Brand Names: Furadantin, Macrobid, Macrodantin What is nitrofurantoin? Nitrofurantoin is an antibiotic that fights bacteria in the body. Nitrofurantoin is used to treat urinary tract infections. Nitrofurantoin may also be used for purposes other than those listed in this medication guide.