What you need to know about the FDA’s new guidance for compounding veterinary drugs Part II
The FDA recently published Guidance for Industry #256: Compounding Animal Drugs from Bulk Drug Substances. It can get complicated, and here’s more of what you need to know.
NEWStat recently published a story about the US Food and Drug Administration (FDA) Guidance for Industry #256: Compounding Animal Drugs from Bulk Drug Substances (GFI #256). Itâs a complicated issue, and many of our reader still have questions about what it means and how it affects their practice.
So NEWStat spoke with Amber McCoig, DVM, MPH, Senior Veterinary Medical Officer, Science Policy, Office of the Director at the FDA Center for Veterinary Medicine, to find out more.
One question that cropped up was, what exactly is a bulk drug substance?
According to McCoig, a bulk drug substance is the active ingredient in a compounded drug. âTheyâre unapproved drugs.â McCoig said. âThey havenât been reviewed by FDA.â
âI think that a lot of veterinarians have the misconception that compounded drugs are really just tailored a specific drug for their patient, and theyâre equivalent to approved drugs, but kind of tweaked,â she said.
The FDA opened their draft guidance for public review in 2019 and received more than 2200 comments.
McCoig said they spent âa long timeâ going through those comments.
âWe wanted to make sure that we were seeing the issues that veterinarians specifically had and that we were able to address those,â she said. âWe recognize that veterinarians need to compound drugs because they treat such a wide variety of species and so many different diseases.â
âSo we wanted to be responsive to vetsâ needs and make this guidance a balance of making sure that safe drugs are used and that weâre considering the safety of the animal patients, but also addressing veterinariansâ needs and recognizing that that there is some room for compounded products.â
McCoig said there was some confusion about the bulk drug substance list. âVeterinarians were concerned that that would apply to patient-specific prescriptions.â Patient-specific prescription are Individuals prescriptions that veterinarians send the pharmacy for just one animal or one group of animals. McCoig said the bulk drug substance list does not apply to one-off patient-specific prescriptions. âThat list only applies to office stock.â
Office stock are medications that could be sitting on shelf in a practice for an unknown length of time. âWe donât know the stability of those products because, again, these are unapproved. No one has looked at them. So we donât know the stability or the efficacy of those products,â McCoig said, and thatâs of concern to the FDA. âIf a practice has that medication on the shelf and over time distributes it to 50 different patients then thatâs 50 more patients that could be exposed to a potential problem.â
âUnless itâs a copy of an approved product, we donât limit what bulk drug substances are used in those patient-specific prescriptions,â McCoig said. âSo really itâs petty open what vets can do for that particular patient, and we think that thatâs a way that vets can have access to what they need for the patients.â
Approved products in this case mean patented drugs manufactured by pharmaceutical companies that have been reviewed and approved for animal use by the FDA. Â And a compounded drug canât use the same active ingredient in the same route of administration as an FDA-approved animal drug.
When would a copy be needed? Sometimes thereâs a drug thatâs approved for humans that a veterinarian could use in an extra label manner, and it might have an ingredient that canât be used in that particular species.
McCoig offers Xylitol as an example. âItâs in some drugs, but itâs toxic to dogs so if an approved drug has it you wouldnât want to use it. If you needed the same ingredient in a product that contains xylitol, youâd be able compound that drug for a dog,â she said. âThereâs a lot of times where veterinarians will take the human approved drug such as human gabapentin off the shelf and repurpose it for use  in an animal, but in this case, that human drug contains xylitol. So youâd ask the pharmacist to basically make the same drug, minus the xylitol.â
âIf thatâs the case, then we still allow for that,â McCoig said. âWe just ask that a medical rationale is provided.â That means that the pharmacy would have to note why the approved drug canât be used. They can do that either by calling the vet or the vet can just put it on a prescription if thatâs easier for them. âWe wanted to make sure that that burden is not on the vets.â
âWe want to make sure people know that the FDA recognizes that thereâs a need to compound from bulk drug substances, and we want this policy to be flexible so that veterinarians can have what they need when they need it,â she said. âAnd weâre open to listening.â
âOur primary goal is to make sure the veterinarians have access to what they need.â
Photo credit: © dreamsquare/iStock/Getty Images Plus via Getty Images