Draft Guidance for Industry – GFI #256B – Compounding Animal Drugs from Bulk Drug Substances: Compounding under CGMP in Federally-Registered Facilities

For those of us in the Animal Drug world, we know it is unusual to hear much regarding compounding of animal drugs. Generally speaking, Animal Drug Compounding is prohibited; in accordance with GFI #256, “animal drugs compounded from bulk drug substances by pharmacists and veterinarians do not meet certain important requirements of the Federal Food, Drug, and Cosmetic Act (FD&C Act)…Thus, drugs compounded from bulk drug substances violate the FD&C Act because they are not approved or indexed, are not made according to CGMP, and cannot satisfy the FD&C Act’s adequate directions for use provision (which requires, among other things, that a prescription drug have FDA-approved labeling).”

However, FDA’s Center for Veterinary Medicine (CVM) provides information in GFI #256 for situations in which they would likely use enforcement discretion when Animal Drugs are compounded by veterinarians or pharmacists in State-licensed pharmacies or federal government facilities when no other medically appropriate treatment options exist. Human Drugs can be compounded either in 503A Compounding Pharmacies (for a specific patient) or in 503B Outsourcing Facilities (at a larger scale) that are registered with FDA under section 503B of the FD&C Act; however, 503B Facilities have not previously been allowed for animal drug compounding.

A new (or “addendum”) CVM draft guidance came out, GFI #256B, that when finalized, will be combined with the current GFI #256. It provides some additional information on compounding of animal drugs in federally registered facilities. According to the Federal Register Notice (FRN) 2026-17580, GFI #256B is intended to provide recommendations for the situation where CVM intends to use enforcement discretion for a federally registered facility which compounds animal drugs when it is not a state-licensed pharmacy. These federally registered facilities would be those registered under section 503B of the FD&C Act, as discussed above. GFI #256B includes the specific requirements which must be met for enforcement discretion to be applied.

This is a significant change to the previous stance from CVM, and I, for one, will be surprised if there is no substantial push-back on this change. The comment period for GFI #256B is open until November 27, 2026. All submissions must include the Docket No. FDA-2018 D-4533; additional information on how to provide comments can be found in the FRN.