Nitrofurantoin (Macrodantin, Furadantin, Macrobid) is a prescription antibiotic used to treat urinary tract infections. Nitrofurantoin is available in three forms, Macrodantin, Furadantin, and Macrobid. Common side effects are change in urine color, diarrhea, itching, and headache. canadian-pharmacyka.com buy viagra online cheap