Harmful antibiotics for puppies tetracycline. is allergic to Polymixin B, oxytetracycline, tetracycline . Enrofloxacin (Baytril Rx) and tetracycline antibiotics should not be given to . . . Puppy Food Senior Pet Food Skin Support Small Breed Dog . . we are dependent on these helpful strains of E. . . . chloramphenicol, allopurinol, probenecid and tetracycline . For example, tetracycline can be harmful to a puppy's . . . ” S. . R. . . . . veterinarian before you give a very young dog an an... more