When it comes to horses and Hollywood, equestrians know not to hold their breath for realistic portrayals of riding and horse care. Arbitrary whinnying, improper tack, bouncing riders—horse people know how to practice a bit of cognitive dissonance to sit through the equestrian faux pas often depicted on screen.

But after the Nov. 17 episode of “Yellowstone,” a fictional series following a Montana ranch family, one scene had a demographic of viewers especially worried: equine veterinarians.

“I [watch “Yellowstone”], but I’ll be honest, I have not seen the episode in question,” said Dr. JoAnna Faircloth, BVSc. “I mostly know about it because social media blew up with my vet friends. I think everyone was just reposting: ‘No matter what “Yellowstone” says, please do not give your horse [intramuscular] Banamine!’ ”

The recent episode showed a character treating a rattlesnake bite by administering the drug Banamine, or flunixin meglumine, directly into the horse’s muscle. Veterinarians caution that delivering this particular drug through an injection into the muscle can cause a range of issues, including fatal outcomes.

“It’s become widely known and widely educated in veterinary medicine that we should not be, if at all possible, giving or letting our clients give this medication into the muscle,” Faircloth said. “The biggest worry with it is that it can be very irritating to the muscular tissue, and that can lead to, in some serious scenarios, abscess formation, neck pain and swelling. But the worst case scenario that Banamine is over represented, [as] opposed to other intramuscular injections, for something called clostridial myositis. That is a very serious condition that can be absolutely life-threatening.”

The rattlesnake episode was not the first time Banamine has been mentioned on “Yellowstone,” a show that has a track record for depicting human use of the medication. In one 2019 episode, a character asks for human pain pills, saying he might start to whinny if he takes any more Banamine. In a 2021 episode, the ranch hands convince a veterinarian to give a character that has been stabbed Banamine to relieve his pain.

In response to the social media outcry over the rattlesnake episode, professional rodeo cowboy Glenn Jackson, who performs stunt work for the show, joked about its human use as well, posting “Social media is blowing up about Yellowstone and not giving Banamine in the muscle. Heck I always thought it went in a drink for pain and followed by a chaser.”

While veterinarians acknowledge television shows are of course meant to be entertaining, not directive, they worry that this scene perpetuates an outdated but persistent practice they have been working to correct. Unfortunately, the drug’s own label is another source of misinformation.

“It is labeled to be able to be given I.V. or I.M. in horses, and for years and years—probably right up to about maybe 20 years ago—it was popularly used, even by veterinarians, intramuscularly,” Faircloth said.

But she says that the medical tides have since turned on the practice as reports showed an increased risk for clostridial myositis. On the other hand, administering the medication orally or through an I.V. has been determined to be both effective and present little risk.

“There are many people out there still who are probably educated differently and may continue to view [I.M. injection] as a safe option,” Faircloth said. “But if you’ve seen enough cases of it going wrong, there’s just no point in risking it because of clostridial myositis in particular.

“The irritation caused by injecting Banamine into a muscle sets up favorable conditions for potentially life-threatening clostridial anaerobic bacterial growth,” she continued. “When they get that clostridial myositis, best case is a long hospitalization and intensive wound care, scar tissue formation, etc. The worst-case scenario is they can die despite high-level treatment.”

Administered correctly, Banamine is a medication that should be part of every barn owner’s first-aid kit.

“Banamine is such a useful medication and so effective for many kinds of pain or inflammation in horses, whether that be for colic or for wounds,” she said. “But we definitely would recommend clients use it orally. If they’re very skilled and comfortable at I.V. injections and do that regularly as part of their job or whatnot, that’s also suitable, but avoid the I.M. route, if at all possible.”

For veterinarians hoping to educate horse people on the appropriate use of Banamine—and who are already fighting an uphill battle on a poorly labeled product—the recent rattlesnake drama on “Yellowstone” did them no favors. But they hope that fans who enjoy the show’s typically realistic horse content will spread the word and make this outdated practice as silly and obvious as the fake whinny.