ARe you absolutely SURE she has an infection? There is Interstitial Cystitis which mimics UTIs exactly but isn't. I quetion if your doctor has thought of that as there are 2 & 3 yr old IC patients and Bactrim is an ancient remedy, albeit an antibiotic. Monourol is much newer & is a powder mixed with a small amt of water & it it takes only ONE dose and is not nasty tasting. Cipro is a much newer PILL antibiotic which I take if I get a UTI on top of IC or for Sinus Monurol doesn'twork for, which does not cause so much antibiotic problems.