Demand FDA Set Actual Limits on Antibiotics Fed to Livestock

In a pandemic, public health protection should trump drug makers' interests.

Credit: Darcy Maulsby/iStock

In a pandemic, public health protection should trump drug makers' interests.

About two-thirds of the U.S. antibiotics important to people are sold for use in food animal production. Yet, experts have long warned of the public health threat from regularly exposing herds of thousands, even tens of thousands, of animals to human-class antibiotics in their feed for prolonged periods of time. It’s a near perfect recipe for spurring the development and spread of “superbugs”, or multi-drug resistant bacteria. 


Magnifying the resistance threat is this fact: the U.S. Food and Drug Administration (FDA) lists 89 medically important antibiotics currently added to animal feeds with at least one approved use (technically referred to as an “indication”) where instructions on how long the antibiotic should be given to animals either fail to clearly define a maximum time ("duration") limit, or offer no duration limit at all. Non-existent or vague duration limits on these feed antibiotics leave veterinarians, who are required to sign a de facto prescription for these drugs, without any FDA-approved instructions on when to stop their use. This lack of clear instructions in turn incentivizes drug makers to profit from selling as many of these human antibiotics for feed as possible. Since 2016, FDA has flagged the lack of clear duration limits as a significant problem needing a remedy.

The agency recently proposed its remedy in the form of a draft “concept paper”. Our initial hope for FDA leadership turned to sho

ck and disappointment. We were looking for a strong step forward to expeditiously getting firm time limits on the essential human drugs being added routinely to animal feeds. On closer reading, we saw that the proposal’s actual framework, its lack of specificity, and the inexcusable snail’s pace of its implementation are wholly inadequate. In fact, they diminish FDA’s avowed commitment to steward medically important antibiotics, and in doing so to protect public health. 

All of us are impacted by the overuse and misuse of antibiotics in animal feeds, whether or not we personally consume foods from those animals. We therefore encourage the public to share their concerns about FDA's flawed proposal by the midnight deadline on Friday, June 11th. Use this link. More than 30,000 public comments have been filed already, and it’s imperative to continue putting pressure on the FDA. Below are highlights of the comments NRDC is submitting:

Acknowledge Antibiotic Resistance as a Pandemic

Antibiotic resistance is one of the world’s greatest health threats—and is already considered a deadly pandemic by many. Because antibiotic misuse and overuse are key drivers of the threat, it’s paramount the FDA acts urgently to ensure the labels of all antibiotics of medical importance added to animal feed carry clearly defined duration limits.

Disregarding its many other flaws, the FDA’s proposal on duration limits has a ridiculously slow timeline for implementation. FDA first asked for public suggestions on how to remedy the lack of duration limits in 2016. The agency in 2018 made getting clear duration limits on already-approved feed antibiotics a top priority as part of its 5-year plan to support better veterinary stewardship of antibiotic. The 2021 ‘concept paper’, however, suggests that final FDA guidance on new duration limits will not appear until 2024, after which the agency offers drug makers an additional 4-6 years to put new duration limits on the labels of the the feed antibiotics they sell. For the FDA to respond to pandemic antibiotic resistance with a 14-year timeline simply to get get clearly defined time limits on already approved products is unconscionable, and unacceptable. We urge the FDA to prioritize completion of its work on duration limits and move with urgency to ensure all animal antibiotics are labeled with clearly defined duration limits by 2023, when the current 5-year plan ends.

Ensure Feed Antibiotics Are Judicious

After touting judicious use for years as the bedrock of its approach to better antibiotic use in food animals, the FDA’s concept paper fails to hold drug makers accountable for the fact that feed antibiotics sold without clearly defined duration limits would qualify as injudicious use, according to the FDA’s own standards. To ensure clearly defined duration limits, and therefore judicious use of feed antibiotics, we urge the FDA to set a single upper limit for feed antibiotic uses (indications), rather than the range of durations that FDA currently allows drug makers to create for a single indication. We recommend 21 days as the single maximum duration limit to be expected of all medically important antibiotics administered via animal feeds. There’s an FDA precedent in that the agency’s 2003 guidance (GFI #152, page 25) established durations for feed antibiotics of longer than 21 days as a “high extent of use”, and therefore disallowed under that existing guidance. 

As FDA itself has noted, judicious use also means that antibiotics should not be added to feed without a specific 'etiologic agent', or bacterial cause of disease, having been identified. At least 13 of the 89 feed antibiotic uses that currently have no defined duration limit are for ‘disease prevention’. According to the FDA’s own definitions, however, feed antibiotics for disease prevention are not judicious uses. Meanwhile, all antibiotic use for disease prevention becomes illegal in the European Union at the outset of 2022, apart from very limited exceptions. As part of its efforts to put defined duration limits on all animal antibiotics, we urge the FDA to explicitly identify already approved feed antibiotics of human importance for disease prevention as injudicious, and then direct drug makers to withdraw its approvals for these indications.

Prioritize Public Health over Drug makers’ Interests

Before the FDA is asked to approve a new antibiotic use in food animals, the agency requires the the drug maker to submit evidence that the proposed duration of use will be safe in terms of its impact on the human population. In this concept paper (page 9), however, the FDA fails to apply the same public health safety standard to the revised language that drug makers will be asked to offer for the 89 already-approved uses of antibiotics in animal feed. Instead, the FDA is proposing to ask drug makers to identify new duration limit language based on an antibiotic’s efficacy for that indication. Rather than public health, FDA is clearly choosing to prioritize the financial interests of drug makers in profiting from the sale of more rather than fewer antibiotics, and the interest of  livestock producers in continuing to use antibiotics injudiciously. We urge the FDA to apply the same public health-based safety standard to duration limits on already-approved feed antibiotics as they would require of drug makers applying for approval of new uses of the same drugs.

A recently published analysis shows a detailed pathway for the FDA to ensure all animal antibiotics could have clearly defined duration limits by the end of 2023, seven years earlier than the timeline laid out in the FDA’s existing proposal. To fully meet the health threat posed by antibiotic resistance, we urge the FDA to work harder and quicker to meet this goal. An essential first step is for the agency to write a more concrete plan with more a more ambitious, more detailed timeline.

If drug makers prove unwilling to move with the same degree of alacrity to get firm duration limits in place on their products, ensuring those feed antibiotics are used judiciously, then the FDA should use its authority to withdraw their antibiotics from the marketplace. When it comes to duration limits, the FDA needs to put public health and not profit-seeking drug companies in the driver's seat. 


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