Ivermectin is used once a month . They do sell Fenbendazole for dogs at tractor supply with no prescription needed as an alternative . I believe the dose for Fenben for dogs is 50 mg per kg for 3 days in a row every month . I rotate between moxi and Fenben for my dogs each month . They have been wormed since puppies and get tested every year . Moxi I get from vet and Fenben I get over the counter .