Page 108 - Jan_2020

BANAMINE ADMINISTRATION OPTIONS
“To avoid risk for this kind of infection, flunixin products like Banamine should never be injected into the muscle,” says Tia Nelson, DVM (Helena, Montana). “They can be given intravenously or orally. There is a Banamine paste, and I encourage people to use it if they want Banamine on hand in case their horse colics. In an emergency, the injectable form of Banamine can be given off-label orally (squirted into the mouth),” she says.
“Flunixin is readily absorbed from the GI tract and works about as fast as when given IM, but IV administration gives fastest response (which is usually what you want in a horse with colic). Flunixin is somewhat irritating to mucosal tissues; you shouldn’t give it very often orally or it may cause ulcers (partly because it’s irritating and partly due to the basic pH). But if you need to get Banamine on board and don’t know how to give it IV, you could squirt the injectable drug into the horse’s mouth
– rather than risk an IM injection. It’s not labeled for oral administration; however, it’s labeled for IV only.”
The liquid form is absorbed readily through mucosal tissues of the mouth and probably is effective even quicker than
the oral paste. “IV injection, by someone who knows how to do it, is the best route, but don’t try it unless you know what you are doing because if any of this solution leaks out of the vein, you have another
big problem. If horse owners need to keep some on hand, and have a prescription for it, and are giving it at home, they need to
be confident in their ability at giving an IV injection. For most of my clients, the paste is safer and simpler to have on hand, without potential for this reaction.
If some of the drug slips out of the
vein into the surrounding tissue, it burns and damages that tissue, creating serious swelling and blocking the vein. “This may wreck the vein (ending up with jugular vein thrombosis), but that’s not a life-threatening thing, compared to a clostridial infection that may kill your horse. Any time you can avoid a problem, it’s better than trying to fix it afterward,” Nelson says. The old saying, “an ounce of prevention is worth a pound of cure,” is very true in this instance.
This mare developed a fever and a swollen neck after an intramuscular Banamine shot. Incisions were made to open up the area for drainage and to get oxygen into the infection, since bacteria thrives in damaged tissue with no oxygen supply. The mare survived, but with scars and some muscle atrophy.
but it is a risk. I have seen three cases and all of these horses were very sick and toxic. There is often a fair amount of swelling at the injection site. The typical ‘calling card’ of clostridial myositis is gas bubbles under the skin. It feels like Rice Krispies. If you ever feel gas under the skin on a horse that’s recently had an intramuscular injection, this is serious and warrants an emergency visit to the veterinarian. It can make a big difference in the outcome
if you can start treating it early, to reduce the extent of complications.”
The most recent case he’s seen was when a horse owner called to say her horse colicked a couple days earlier. “She had some Banamine, but couldn’t give an injection in the vein so she gave it in the muscle. The next day, her horse was a little stiff-necked and sore at the injection site, so she gave some penicillin, which was fine. Two days after the Banamine shot was when she called me. The mare’s neck was swollen on both sides and she had a fever of 104, and a toxic line on the mucous membranes on her gum.
“The owner told me what had happened,
so I was looking for evidence of gas under the skin – because I was thinking it probably was
a clostridial myositis. I didn’t find any gas near the injection site, but finally found a pocket of gas under the skin by her withers. The gas had travelled up and along the neck, clear to the withers. I prepped the skin at the injection area and blocked it with anesthesia as best I could and made incisions through the skin and partway down into the muscle with a big scalpel,” he says.
One of the important aspects of treatment is to open up the area and get oxygen down into the infection. Those bacteria don’t like oxygen. They thrive in damaged tissue with no oxygen supply.
He made several deep incisions and dissected down into the muscle. “Then suddenly my finger fell into an opening and I thought maybe
I’d been unlucky enough to drive my finger into a large blood vessel. I was afraid it might start bleeding, but realized I had to pull my finger out. When I pulled my finger out of the wound, gas rushed out of that hole and the stench was foul. So, I opened it up even more, grabbed chunks of necrotic muscle tissue and dragged it out. I opened the infected area as best I could, then packed it with penicillin- soaked gauze and started the mare on penicillin injections. Another drug that is very effective against clostridia bacteria is metronidazole,”
he explains. A horse with this kind of infection would also need a tetanus booster.
“With this mare, I got lucky. She survived, but with large scars on the side of her neck and some atrophy in those muscles, but all in all she did pretty well. The most important thing in dealing with this type of infection is getting oxygen into the affected tissues, and that’s why you see photos of horses with large, gaping incisions into those areas – for oxygen and drainage,” he says.
“If a person has access to a hyperbaric oxygen chamber, that would be ideal, but most people are not close enough to one, and/or can’t afford those treatments. This type of oxygen therapy is an excellent treatment modality for clostridial myositis.”
If the injection site and subsequent incisions are on the neck, the horse will have a very sore neck for a while and it might be painful to put his head down to eat and drink. “You need to help these horses by placing feed and water a little higher for easier reach. If the horse is in decent body condition to begin with, even if
he can’t eat very well, it will take several days before he starts dropping muscle condition
and body weight. But supportive care to help him eat and drink can keep him from losing too much weight. Depending on where the injection was that caused the infection (neck or hindquarters), you may or may not be able to give IV fluids,” he says.
“With this particular mare, with infection in the neck, venous access was not an option because of all the infection and gas under the skin. Trying to get into a vein with a catheter would risk a more serious problem. You can clean the surface of the skin, but you can’t clean out the contaminated subcutaneous tissue. A person can always give fluids and nutrients via stomach tube (nasogastric tube), which would be safer in this situation than an IV. There are some tubes that are designed to be left in place for several days, and the horse could be fed that way,” says Randall.
The mortality rate with this type of infection is fairly high, so it’s important to get your veterinarian involved as soon as possible, to increase the chances of turning it around quicker.
104 SPEEDHORSE, January 2020
EQUINE HEALTH