FDA Draft Guidance Brings Remaining OTC Medically Important Antimicrobials for Animals Under Veterinary Oversight 
The draft guidance outlines the process for changing the approved marketing status from over-the-counter (OTC) to prescription (Rx) for antimicrobials that are medically important for humans and used in animals.

The guidance for industry (GFI) #263, “Recommendations for Sponsors of Medically Important Antimicrobial Drugs Approved for Use in Animals to Voluntarily Bring Under Veterinary Oversight All Products That Continue to be Available Over-the-Counter,” explains the recommended process for voluntarily bringing the few remaining approved animal drugs containing antimicrobials of human medical importance, such as injectables, under the oversight of licensed veterinarians.
This guidance is part of the FDA’s Five-Year Plan for Supporting Antimicrobial Stewardship in Veterinary Settings and builds upon GFI #213, which outlined the process for animal drug sponsors to work collaboratively with the FDA to voluntarily change OTC medically important antimicrobials used in the feed or drinking water of food-producing animals to Veterinary Feed Directive (VFD)/Rx marketing status and eliminated the use of these products for production purposes (e.g., growth promotion). These changes took effect in January 2017.
The FDA is proposing a two-year implementation period for the marketing status changes outlined in GFI #263. The agency intends to reach out to affected stakeholders and state partners to answer questions about the recommended process for voluntarily making these marketing status changes.

Current Goods Manufacturing Practice (CGMP)

What You Need to Know About the FDA Regulation: Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Food for Animals (21 CFR Part 507) Guidance for Industry, Small Entity Compliance Guide #241
Guidance for Industry Small Entity Compliance Guide Veterinary Feed Directive Regulation Questions and Answers? Guidance for Industry #120; Small Entity Compliance Guide
Confined Space Entry on a Farm