Sara:  Until Dr. Hale answers, I have to weigh in with one of my pet
peeves:  doctors reflexly prescribing the latest thing in their drug
closet when numerous other equally effective well tested meds are
available.  In the case of monurol, it is being pushed because it is a
one-dose treatment, and that certainly is convenient.  However, it is not
more effective than many other antibiotics for UTI which we know are
compatible with breastfeeding.  I would ask the mother to find out from
her OB why he/she prescribed that particular med, and to tell him/her that
breastfeeding is important to her and she would prefer an antibiotic which
is known to be compatible with continued breastfeeding.  Good luck, Alicia
Dermer, MD, IBCLC.