anti-inflammatories | Horse Racing Free Tips

Study: Surgical Intervention For Specific Poll Injuries Is Often Successful

Horses suffering from poll injures involving the cranial nuchal bursa often behave in very specific ways, reports EQUUS magazine. They often stretch down their neck and carry their heads low, and they are often reluctant to flex through their poll and avoid being on the bit.

Bursa are fluid-filled sacs found between bones. The soft tissue is designed to ease friction between the two structures. The cranial nuchal bursa is located between the nuchal ligament and the atlas vertebra.
Inflammation in this bursa, called cranial nuchal bursitis, can cause pain, limited flexion and decreased athletic performance. A study has shown that surgical intervention is often successful in treating this injury.

Dr. José M. García-López, of Tufts University, led a research team in reviewing the records of 35 horses diagnosed with cranial nuchal bursitis over the past 25 years.

The horses were between 5 and 22 years old, with a median age of 13. The majority of the horses were sport horses, primarily competing in dressage, which García-López noted may support the idea that specific ways of going could encourage the development of cranial nuchal bursitis.

Records showed that 14 of the horses were treated with anti-inflammatories, while the rest underwent a minimally invasive surgery to correct the problem. The surgery, called a bursoscopy, allows a surgeon to flush and remove debris from the bursa.

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The researchers found that 78.6 percent of the horses which underwent surgery returned to their previous level of work, while 66.7 percent of horses which received only medication were able to return to work. The horses that responded well to non-medical management generally presented with solely fluid accumulation, with minimal debris in the bursa or synovial thickening.

García-López and his team concluded that horses with bursa inflammation alone could be treated with anti-inflammatory medication; however, if debris is present in the bursa, surgery is recommended. The sooner the surgery is performed, the more likely the horse will return to an athletic career.

Ins And Outs Of Transdermal NSAID In Horses

If you're fighting tooth and nail to administer oral medications, the introduction of a transdermal option often pleases horses and handlers alike. Transdermal medications are applied to the surface of the skin, typically in the form of an ointment or gel, so as to allow gradual absorption into the body. Are you considering transdermal medications, especially anti-inflammatories? If so, it's important to understand how these drugs are absorbed and eliminated, particularly if your horse is involved in competition and subject to stringent drug withdrawal times.

In the U.S., a transdermal formulation of the nonsteroidal anti-inflammatory (NSAID) diclofenac sodium, sold under the brand name Surpass, is approved for use in horses. Recently, a transdermal product containing flunixin meglumine was approved in cattle and is therefore available for off-label use in horses. Flunixin meglumine is often called by the common brand name Banamine.

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To assess how transdermal delivery of flunixin meglumine behaves in the body compared to other routes of administration (e.g., oral, intravenous, intramuscular), researchers applied a 10-mL dose of transdermal flunixin meglumine along the midline of the horse's back, from the withers to the tailhead. This was equivalent to a standard 500-mg dose of flunixin meglumine per horse. *

Blood and urine samples were intermittently collected for up to 96 hours after administration to measure the intricacies of how the medication is absorbed and cleared, a science known as pharmacokinetics.

“Transdermal application was well tolerated in all six study horses, with no horse showing any negative dermal effects,” said Peter Huntington, B.V.Sc., M.A.C.V.Sc., director of nutrition at Kentucky Equine Research.

In terms of the drug's behavior, here's what the research team found:

The maximum concentration of flunixin meglumine in blood was only an average of 515 ng/mL, which is much lower than oral and intramuscular concentrations. Oral administration of a comparable dose of flunixin meglumine results in average concentrations ranging from 3,340 to 7,200 ng/mL. Intramuscular flunixin meglumine reaches average concentrations of 1,799-3,269 ng/mL.
Transdermal absorption into the horse's bloodstream was slow, an average of 8.76 hours. Oral flunixin meglumine requires less than an hour to be absorbed.
Elimination (clearance) of transdermal flunixin meglumine was also much slower than other routes of administration. It took 22 hours for half of the drug to be eliminated from the bloodstream (called the half-life) when the transdermal formulation was used. In contrast, the intravenous half-life is 3.38-9.68 hours.
The data also showed that transdermal flunixin meglumine has unique pharmacokinetics called “flip-flop kinetics” in which the rate of absorption is actually slower than the rate of elimination.

“Based on this data, it is not surprising that flunixin meglumine and a metabolite were still detectable in urine 96 hours after application. This means that the withdrawal time for transdermal flunixin meglumine would be longer than for any other route of administration,” said Huntington.

He added, “Even though the blood concentrations of flunixin meglumine were lower compared to those achieved by other routes, the slow, variable absorption and 'flip- flop kinetics' indicate the medicine applied transdermally persists in the body longer than if given by other routes of administration. More excretion studies in exercising horses are needed before safe withholding periods before competition can be established.”

Despite the low circulating drug concentrations, transdermal flunixin meglumine still elicited an anti-inflammatory effect for up to 72 hours after application.

In terms of safety, Huntington warned, “Considering that transdermal flunixin meglumine is indeed absorbed systemically, this means that horses are at risk of the common side effects associated with NSAIDs administered by other routes: gastric ulceration, dorsal colitis, and disruption of the intestinal microbiome.”

Horses treated with any type of NSAID by any route of administration, including transdermal, would therefore benefit from a digestive tract supplement containing antacids, stomach-coating agents, and a hindgut buffer.

“These supplements reduce the risk of damage to the gut lining or change in the microbiota resulting from NSAID use,” Huntington advised.

*Knych, H.K., R.M. Arthur, S.R. Gretler, D.S. McKemie, S. Goldin, and P.H. Kass. 2021. Pharmacokinetics of transdermal flunixin meglumine and effects on biomarkers of inflammation in horses. Journal of Veterinary Pharmacology and Therapeutics:12993.

Reprinted courtesy of Kentucky Equine Research. Visit ker.com for the latest in equine nutrition and management, and subscribe to Equinews to receive these articles directly.

The post Ins And Outs Of Transdermal NSAID In Horses appeared first on Horse Racing News | Paulick Report.

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Cellulitis: A Challenging Condition To Cure

Cellulitis is a sudden, painful skin infection that requires aggressive, immediate care. Most commonly affecting the hind legs, many horses recover readily, but complications are possible, and chronic flare-ups are a possibility.

Cellulitis occurs when bacteria penetrate the epidermis of the skin and multiplies in the subcutis, which is made up mainly of fatty and connective tissues. Primary cellulitis has no specific point of origin and exactly how it penetrates the skin is often unknown. Secondary cellulitis occurs when bacteria enter tissues through a known route, like a wound or surgical incision.

Cellulitis can be caused by a variety of bacteria and needs to be treated promptly. Left untreated, the infection can affect bone, tendon or synovial structures. Sepsis and laminitis can also occur.

Signs of cellulitis include:

Dramatic swelling that comes on rapidly and feels firm
Heat
Pain that tends to appear when the horse is asked to step forward rather than bear weight
Fever
Wetness: the swelling can progress rapidly to the point where fluid leaks from cracks in skin that is overstretched

A vet may take X-rays or do an ultrasound to rule out other possible issues like a joint infection or fracture. He or she may also culture the fluid weeping from the leg; this will help determine what bacteria is involved so that the proper antibiotic can be administered.

The primary treatment for cellulitis is intravenous antibiotics, as well as nonsteroidal anti-inflammatories to help with pain and swelling. Cold hosing or ice boots or bandaging can also help.

Horses with secondary cellulitis tend to recover more rapidly. Though some cases of cellulitis can be managed at home, severe cases may need to be referred to an equine hospital.

Horses that have had even one episode of cellulitis become susceptible to chronic cellulitis, specifically in the same limb, whether the skin was permanently damaged from the extreme swelling or because circulatory and lymphatics systems have been damaged to the point that they are unable to mount an immune response. Horses that have had cellulitis even once should be monitored carefully as even the tiniest wound may initiate a new round of cellulitis.

Tips to avoid cellulitis recurrence:

Turn out the horse as much as possible in dry condition
Use shampoo sparingly when bathing
Avoid sharing grooming tools and sterilize them regularly