Iam 87 & have had Interstitial Cystitis since I was 27. Thus acts EXACTLY like a UTI. I also had UTIs for years before beginning Prolaprim & it has been years now since a UTI, but I still have IC as it is NOT curable. Are you SURE she has UTIs? They are helped by antibiotics altho Bactrim is an OLD one. Why not try a newer one like CIPRO (pills) or Monurol (a powd. mixed w/water & only needs to be taken once & tastes ok). Cipro is used extensively but Bactrim was used 20 yrs ago & can cause a colitis..as it did on me. Bladder pain/burning,frequency is horrible & I feel SO bad for your daughter. You may email me if you wish. I am a counselor for IC and other things which follow it often & counsel about 200 women. I have seen about 60 urologists, have had all they DO for IC and talk to ladies who THOUGHT they had UTIs & found they had IC. IC is NOT an infection, so doesn't show anything on the microscope slides while UTIs ARE but the symtoms are identical.