Which antibiotic is contraindicated specifically in large breed dogs?

Enrofloxacin is specifically contraindicated in large breed dogs because it has been associated with cartilage damage and developmental orthopedic diseases in these breeds, particularly when given during their rapid growth phase. This is particularly concerning for large breed puppies, as their bones and joints are still developing and can be adversely affected by certain medications. Studies have shown that enrofloxacin may lead to conditions such as osteochondrosis and can negatively impact the overall growth and skeletal development of these dogs.

In contrast, the other antibiotics listed—amoxicillin, doxycycline, and cefalexin—are not known to have similar contraindications in large breed dogs and are generally considered safe when used appropriately. They do not exert the same effects on developing cartilage, making them preferable choices in treating infections in these breeds.