What is the Green Book used for?

The Green Book is utilized primarily as a comprehensive guide on animal drug products that are approved by the FDA. This resource provides essential information about veterinary drugs, including their approved uses, dosages, and safety considerations. It serves as a critical reference for veterinarians and others involved in the care of animals, helping them make informed decisions regarding the medications they prescribe or administer.

In contrast, the other options relate to different aspects of pharmacology and healthcare but do not accurately define the purpose of the Green Book. For instance, drug pricing and FDA-approved medications pertain more to human pharmaceuticals, and vaccine efficacy involves a different domain of medicinal review aimed at human health. The Green Book specifically targets the veterinary field, thus distinguishing its purpose and applicability in comparison to other medical reference materials.