I have used d-mannose and Utiva cranberry supplements for years and that combination is very effective for prevention once you clear the UTI. Utiva contains 36 PAC's which is equivalent to 9 glasses of cranberry juice. I have also used Hiprex (methenamine mandelate) which is an anti-infective not an antibiotic. It causes no antibiotic resistance and is a very old drug which is now being used safely.