My Great Dane/husky mix suffered from constant UTIs -- until I started her on UT Strength from VetriScience. She weighs 117 lbs, and gets 1 tablet a day. Granted it says it is not for continued use, but the minute I take her off of it, she starts phantom peeing and becoming very destructive (she chewed up part of our Pergo floor!). The advantage of these pills is that they are doggie friendly flavored, however, I may just try plain old cranberry pills when this bottle is done.
Here's a link
http://www.vetriscience.com/ut-strength-dogs.php plus a list of the active ingredients
Uva Ursi-200 mg
Chanca Piedra (Phyllanthus niruri)Powder-150 mg
Cranberry Juice Extract-100 mg
Marshmallow (Althaea officinalis) Root Powder-100 mg
L-Methionine-100 mg
Corn Silk Powder-60 mg
Ascorbic Acid (Vitamin C)-60 mg
Dandelion (Taraxacum officinale) Whole Plant Powder-50 mg
Olive Leaf (15% Oleuropein) Extract-50 mg
Lactobacillus Acidophilus-35 million CFU