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What is the Difference Between 503a and 503b Compounding Facilities in Regards to Veterinary Hospitals in Montana?

Catie has her A.S. in veterinary technology and has worked in the veterinary field for nine years.

The Law

In the State of Montana, compounded medications must be prescribed to order for specific patients. Only medications compounded in a 503b facility can be fulfilled as a stock order for in clinic distribution as needed for multiple patients. Aka "office use".

The following states (as of the first quarter of 2020) also require only patient specific compounded prescriptions.





New Mexico

New York



Rhode Island

South Dakota

Washington DC

West Virginia


The Difference


Only patient specific prescriptions can be compounded by a 503a facility. No office use prescriptions can be filled by a 503a facility.

These facilities are regulated by individual state pharmaceutical boards. They have fewer requirements on quality control (this does not imply a poorer product than a 503b product), their building facilities, and are inspected by the FDA when an inspection is warranted.


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Office use, or in clinic use, compounded medications can only be ordered from 503b facilities.

These facilities are managed by the FDA, have more strict policies, procedures, and random inspections. 503b facilities are required to keep stringent documentation for traceability purposes among a slew of other differences.

But Why?

In 2012, a U.S. compounding facility produced contaminated bulk medications that infected over 700 patients with fungal meningitis and has tallied 100 deaths to date.

Here is a link to the FDA's press release following the trial that handed out many federal offense convictions in 2018: U.S. Department of Justice Press Release

In 2009, twenty one Venezuelan polo horses lost their lives due a mathematical/clerical error made by a bulk compounding facility.

As a result, the FDA tightened the reigns on bulk compounds nation wide in November of 2019 with GFI #256.

List of 503b Facilities that Compound Medications for Veterinary Providers

I have knowledge of the following two 503b facilities that can be used legally in Montana. Follow the links to see what medications they compound.

Atlas Pharmaceuticals (Purchased by Covetrus Compounding)

Epicur Pharma

I do not have any experience with the following 503b compounding pharmacies:

Wedgewood Connect

RXQ Compounding

KRS Global Biotechnologies

  • It was hard to navigate their online catalogue

Olympia Pharmaceuticals

  • Google for link

Pharmaceutic Labs

Wells Pharmacy Network

I went to every website affiliated with (as of 07.10.2021) the FDA's list of registered 503b outsourcing facilities and spent ten to thirty seconds navigating each site to find whether the facilities actively marketed towards veterinarians. The entire list of every 503b facility can be found on the FDA's website by following this link. Throughout my research, I have found no regulations indicating that a veterinarian cannot order from any registered 503b facility whether marketing towards veterinarians or not- but proceed with any business of your own at your own risk.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

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