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Saying Farewell to the Famous Horse Tweet

During the COVID-19 pandemic, there were instances of patients trying to get access to ivermectin, believing that it was a miracle drug for the disease. In response, the FDA tweeted, “You are not a horse. You are not a cow. Seriously, y’all. Stop it.” The agency also included a link to a page explaining why ivermectin should not be used to treat or prevent COVID-19. It was a brilliant move – a clear message on an important topic with a touch of humor – and it went viral.

Unfortunately for the FDA, their stance on ivermectin led to a lawsuit. Three doctors (Mary Talley Bowden, Paul Marik, and Robert Apter) claimed that the FDA overstepped its authority, interfered with their ability to prescribe, and harmed their reputations. Bowden lost admitting privileges at a hospital; Marik lost positions at a medical school and a hospital; and Apter was referred to physician regulatory boards for discipline – all because of their support for ivermectin to treat or prevent COVID-19.

The lawsuit was initially dismissed, with a district court saying that the FDA was protected by sovereign immunity. The decision was reversed in the Fifth Circuit Court of Appeals in September 2023, with Judge Don Willett stating: “FDA is not a physician. It has authority to inform, announce, and apprise – but not to endorse, denounce, or advise. The Doctors have plausibly alleged that FDA's Posts fell on the wrong side of the line between telling about and telling to.” Thus, the lawsuit was free to proceed.

Many would argue that the FDA was doing what it felt necessary to protect public health. However, the FDA doesn’t actually have legal authority to limit off-label use of a drug approved for human use.

Ivermectin is FDA approved for human use to treat certain conditions associated with parasitic worms. It is available on prescription only and can have severe side effects. Veterinary ivermectin, however, is readily available to purchase over the counter. So when some groups and influencers began endorsing the use of ivermectin against COVID-19 (despite numerous studies saying it had no effect), some people turned to ivermectin formulations meant for animals. In August 2021, the FDA Center for Veterinary Medicine sent letters warning veterinarians and animal product retailers that people were becoming ill from using highly concentrated ivermectin formulations meant for animals. In a high profile incident in 2023, Danny Lemoi – an influencer who championed the use of ivermectin and was regularly taking veterinary ivermectin – died reportedly because of an oversized heart, which can be a side effect of ivermectin. His final post to his followers was: “HAPPY FRIDAY ALL YOU POISONOUS HORSE PASTE EATING SURVIVORS!!!”

Why did attention around ivermectin reach such a frenzy – particularly amongst the anti-vaxxer crowd? An article in The Washington Post explained that the drug became politicized as an “anti-establishment alternative” to vaccination. Columnist Philip Bump wrote, “To justify rejecting effective vaccines, you need to both denigrate the vaccines’ efficacy and propose an alternative.” He went on to explain: “The effect of encouraging people to rely on ivermectin was the same as asking them to rely on wishing upon a star: Some would live and might credit ivermectin for their survival. But that was simply coincidental. Those who might have lived had they been vaccinated were not around to instruct people that ivermectin didn’t work.”

Speaking to The Seattle Times, David Boulware, a professor of medicine at the University of Minnesota, explained that the use of ivermectin reflected desperation at the time. “People want a therapy, need a therapy, and they don’t really have access to other therapies. . . . [Ivermectin] had a little bit of data, a little bit of science behind it, where propaganda could take off and really kind of exploit the pseudoscience to really promote it.”

Debates on ivermectin versus COVID-19 continue to this day, but numerous studies have shown no clinical benefit, so it is frustrating to see the FDA backed into a corner over the matter when the agency had public health in mind. In March 2024, the FDA reached an agreement in the lawsuit; the doctors would dismiss their claims but the FDA had to remove social media posts and consumer directives concerning ivermectin and COVID-19 – this includes pages that gave information on why ivermectin should not be used to treat COVID-19, as well as the famous horse tweet.

The Los Angeles Times described the move as a “major blunder” that could lead to the FDA being undermined in the future. “The agency’s duty is to stand in the way of anyone desiring to push unsafe and ineffective drugs and devices at unwary consumers for profit, and also to stand in the way of a perverse idea that personal freedom includes the freedom to be gulled by charlatans.”

The move emphasizes the challenges of communication in the healthcare space. Even when the case was initially dismissed, the district court noted that “FDA could have, and perhaps should have, been more prudent in their communications.” Part of the problem was that the FDA did not acknowledge in its posts that ivermectin was approved for human use.

But there are wider questions here – if the FDA is not to discourage off-label use, does this open up risks to patients by allowing manufacturers to challenge the FDA when they themselves are pulled up by the agency for promoting off-label use? And what about so-called snake oil salesmen?

The article in The Los Angeles Times says: “The agency’s protective role has often been questioned by purveyors of useless but lucrative nostrums, such as the stem cell treatments peddled by unlicensed clinics claiming to treat everything from multiple sclerosis to Alzheimer’s to erectile dysfunction, for none of which stem cell treatments have been scientifically validated.”

The FDA advises consumers to be cautious around unlicensed clinics, but the article goes on to say: “Stem cell hucksters would undoubtedly prefer for that cautionary language to be removed. The 5th Circuit’s ruling might give them a leg to stand on. That won’t be good for anybody. The FDA should have pursued the ivermectin case instead of settling. That would have shown that it’s still devoted to its consumer protection purpose.”

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About the Author
Stephanie Vine

Making great scientific magazines isn’t just about delivering knowledge and high quality content; it’s also about packaging these in the right words to ensure that someone is truly inspired by a topic. My passion is ensuring that our authors’ expertise is presented as a seamless and enjoyable reading experience, whether in print, in digital or on social media. I’ve spent fourteen years writing and editing features for scientific and manufacturing publications, and in making this content engaging and accessible without sacrificing its scientific integrity. There is nothing better than a magazine with great content that feels great to read.

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