The U.S. Food and Drug Administration released a draft guidance for industry to provide recommendations on how animal drug sponsors may voluntarily establish a defined duration of use for certain approved medically important antimicrobial animal drugs with indications that currently lack a defined duration of use. 

When a drug lacks a defined duration of use, it means the labeling does not include information about how long a product can be administered for an approved indication.

As of Sept. 25, there are nearly 100 approved animal drug applications for medically important antimicrobials that have one or more indications without a defined duration of use. 

The recommendations in the draft guidance only affect medically important antimicrobials approved for use in or on the feed of food-producing animals.  All approved uses of medically important antimicrobial drugs in other dosage forms (e.g., injectable, intermammary, tablet, etc.) already have appropriately defined durations of use.

Revising product use conditions of affected products to better target when and for how long a drug may be used to effectively treat, control, or prevent the disease(s) for which the product is indicated provides for the continued effective use of these products while minimizing the extent of antimicrobial drug exposure. These changes support FDA’s judicious use efforts and are intended to help mitigate the development of antimicrobial resistance.

In January 2021, FDA published and sought public comment on a concept paper titled “Potential Approach for Defining Durations of Use for Medically Important Antimicrobial Drugs Intended for Use In or On Feed: A Concept Paper.” FDA considered all information and public feedback received in response to the concept paper during development of this draft guidance. 

FDA is accepting public comments on “Defining Durations of Use for Approved Medically Important Antimicrobial Drugs Fed to Food-Producing Animals,” through Dec. 26. To electronically submit comments to the docket, visit the website and type FDA-2023-D-2925 into the search box. To submit comments to the docket by mail, use the following address. Be sure to include docket number FDA-2023-D-2925 on each page of your written comments.