Antimicrobial sales rise despite pending changes

Agreements between federal regulators and pharmaceutical companies are expected to reduce antimicrobial use in agriculture by the end of this year.

But a report published late last year indicates sales and distribution of antimicrobial drugs for use in livestock, by weight, rose before and after the Food and Drug Administration published its plan for reducing use.

The report states that domestic sales and distribution of antimicrobials approved for use in livestock rose 4 percent from 2013 to 2014, part of a five-year rise of 22 percent. Among the antimicrobials in the same drug classes as those used in human medicine, the one-year rise was 3 percent, and the five-year rise was 23 percent.

The FDA published in December 2013 a three-year plan to eliminate production uses—such as for increasing growth rates or improving feed efficiency—and require veterinarian oversight for antimicrobials that are administered in feed or water and that are in the same drug classes as those used to treat humans. All the companies that own drug approvals described in the proposal have agreed to adjust their approvals so that, by this December, production uses of such drugs will be prohibited, and buying them will require prescriptions or veterinary feed directives.

Those agreements followed an agency warning of regulatory proceedings against holdouts.

Since the FDA published its first report on the yearly total weight of antimicrobials sold or distributed for use in livestock—covering the year 2009—the total weight of antimicrobials sold has gone up in every subsequent year.

The report published in December 2015 lacks any exact figures showing how much of current use would be affected by the coming changes. But overlap among certain figures shows that most of the total amount sold now will require added veterinarian oversight or become prohibited.

Of the 20.8 million pounds of antimicrobials in drug classes shared with humans and sold or distributed for use in U.S. livestock during 2014, about 20.3 million pounds were available over the counter, and 19.8 million pounds were sold for use in feed or water. While the report also indicates almost three-quarters of that total is available for production uses, it does not indicate how much of that total likely was administered for production.

The data have some other limitations, including that the figures show weights of products rather than doses and indicate total sales rather than actual use.

“For example, drug products entering the market may not necessarily be distributed all the way to the farm; veterinarians and animal producers may purchase drugs in anticipation of using them but never actually administer them to animals, or they may administer them in later years,” the report states.

In addition, the agency notes that a “very small” portion of the antimicrobials in that total are approved for uses in non–food-producing animals, such as dogs and cats.

But agency officials are working with partners in the federal government, academia, and industry to gather more information on “how, when, and why animal producers and veterinarians use antimicrobial classes that are medically important in human medicine.” And they plan to collect more information on antimicrobial use and resistance on farms, having proposed requiring that pharmaceutical companies include data on sales and distribution by target animal species.

Asked about the rising weights and the expected changes in drug sales, FDA spokeswoman Megan Bensette provided a statement indicating in part that all antimicrobial drug uses can contribute to antimicrobial resistance development and are public health concerns. She noted that the sales and distribution data “do not translate to actual use,” and pharmaceutical companies have committed to make the described drug labeling changes by December 2016.

Related JAVMA content:

FDA wants species-level antimicrobial data (July 1, 2015)

Antimicrobial sales outpace meat production (June 15, 2015)

Changes coming in antimicrobial use, availability (Jan. 1, 2015)