Prescribing antibiotics for dogs while they are nursing is not recommended. Although some medications are safe for your dog, others can harm her feeding pups. Still, medication might be necessary for a pregnant or lactating dog to save her life.
Antibiotics and Nursing
It is not recommended to give antibiotics to your dog while lactating because the drugs can get in the milk and affect the nursing pups. There are some strong antibiotics that can interfere with bone growth in newborn puppies.
Infection vs. Antibiotics
A dog who is nursing should not be on any medication, but the risks from conditions like a bladder or bacterial infection can do far worse damage to her and the nursing pups if left untreated. Sometimes a dog can develop an infection in her milk duct called Mastitis that can prevent her from nursing her pups and even lead to gangrene. These are a couple of cases where an antibiotic is needed to clear up the infection so your dog can nurse her pups. In these cases, your vet can perscribe medications that are safer than others according to your dog's health and breed. For instance, it is general consensus that a mild dose of Amoxicillin will not harm the puppies or dry up your dog's milk.