I had a UTI that just wouldn't go away. I was on 3 different types of antibiotics for 29 days. I developed C-diff that took 2 months to treat. I was fortunate enough to find a gyno-urologist at Mayo who ran several diagnostics and saw that there was nothing structural going on. I was prescribed 50 mg of Macrobid one time daily for several months. I didn't want to take them that long. I started taking methenamine mandelate (Hiprex) 2 X daily along with 500 mg of Vitamin C which took care of recurrent UTI's. Hiprex is an anti-infective not an antibiotic and has been around a long time. Doctors are returning to this way of reducing bacteria load in the urinary tract and it works quite well.