Drug compounding is the process of combining, mixing or altering ingredients to create a medication tailored to the needs of an individual animal or a small group of animals, and these drugs can play a critical role in veterinary medicine. Compounded animal drugs are typically made by pharmacists or veterinarians. The Federal Food, Drug, and Cosmetic Act (FD&C Act) permits compounding of animal drugs when the source of the active ingredient is a finished FDA-approved drug, and not a bulk drug substance. A “bulk drug substance” is a substance used to make a drug that becomes an active ingredient in the finished dosage form of the drug.
Animal drugs compounded from bulk drug substances are not FDA-approved and have not been reviewed by FDA for evidence that they are safe, effective, properly manufactured, accurately labeled, and adequately packaged. Further, when the compounded drug is for a food-producing animal, FDA has not reviewed evidence supporting conditions of use to protect against drug residues. Finally, unlike sponsors of approved animal drugs, compounders are not required to report to FDA adverse events and product defects regarding animal drugs compounded from bulk drug substances.
However, where there is no medically appropriate drug that is FDA-approved, conditionally approved, or on the Index of Legally Marketed Unapproved New Animal Drugs for Minor Species (indexed) to treat the animal, an animal drug compounded from bulk drug substances may be a veterinary medically necessary treatment.
On November 19, 2019, FDA issued draft Guidance for Industry #256, entitled “Compounding Animal Drugs from Bulk Drug Substances.” The new draft guidance, if finalized, would advise veterinarians on circumstances under which FDA does not intend to take action for certain violations of the FD&C Act when pharmacists and veterinarians compound or oversee the compounding of animal drugs from bulk drug substances. FDA believes this policy, if finalized, would allow the legitimate veterinary medical needs of their animal patients to be met by providing access to drugs compounded from bulk in appropriate circumstances, without undermining the demonstrated safety and effectiveness of approved animal drugs. The agency is also developing the “List of Bulk Drug Substances for Compounding Office Stock Drugs for Use in Nonfood-Producing Animals or Antidotes for Food-Producing Animals.” Under the circumstances of Draft GFI #256, only bulk drug substances on this list can be compounded into drugs for office stock or for antidotes for food-producing animals.