Meclofenamic Acid for Horses: Uses, Dosing & Side Effects

This information is for educational purposes only. Never give your pet any medication without your veterinarian's guidance. Dosing, frequency, and safety depend on your pet's specific health profile.

Meclofenamic acid is a prescription nonsteroidal anti-inflammatory drug (NSAID) used in horses to help reduce pain and inflammation. It belongs to the fenamate family of NSAIDs and has been marketed for horses as an oral granular product, commonly known as Arquel.

Your vet may consider this medication when a horse needs help with ongoing inflammatory pain, especially in the musculoskeletal system. Compared with some other equine NSAIDs, meclofenamic acid has a slower onset of action. Horses may need 2 to 4 days of dosing before the full clinical effect is seen, so it is usually not the first choice when immediate pain relief is needed.

It is absorbed after oral dosing, although feeding before administration can delay absorption. Like other NSAIDs, it works by reducing prostaglandin production, which can ease inflammation and discomfort but can also affect the stomach, colon, kidneys, and other tissues if the drug is not used carefully.

Because its safety margin may be narrower than some other equine NSAIDs, this is a medication that should be used only under your vet's direction, with attention to dose, duration, hydration status, and any history of ulcers, kidney disease, liver disease, or low blood protein.

Meclofenamic acid is used for the oral treatment of acute or chronic inflammatory conditions involving the musculoskeletal system. In practice, your vet may use it for horses with osteoarthritis, chronic lameness, navicular-region pain, or laminitis-related inflammation, especially when a longer-acting oral NSAID plan is being considered.

This drug tends to fit chronic inflammatory pain better than sudden emergencies. Because it can take a few days to show its full effect, it is generally less useful when a horse needs rapid relief for severe colic pain or a fresh traumatic injury. In those situations, your vet may choose a different NSAID or a different pain-control plan.

Some horses respond well to meclofenamic acid when other NSAIDs have not given the desired comfort or when your vet wants an alternative oral option. That said, response varies. The best choice depends on the horse's diagnosis, workload, ulcer risk, kidney function, hydration, and any competition medication rules that may apply.

If your horse has chronic stiffness, laminitis discomfort, or recurring lameness, your vet may also pair medication decisions with hoof care, exercise changes, body condition management, imaging, or joint-directed therapies. Medication is often only one part of the plan.

The commonly cited equine dose for meclofenamic acid is 2.2 mg/kg by mouth once daily for 5 to 7 days. A practical rule sometimes used in equine references is 0.5 mg/lb once daily, which equals about 500 mg for a 1,000-lb horse. Your vet may adjust the plan based on body weight, response, and risk factors.

This medication is usually given as an oral granular preparation. Because feeding before dosing can delay absorption, your vet may give specific instructions about timing with feed. Do not change the dose, double up missed doses, or continue beyond the prescribed period unless your vet tells you to. With NSAIDs, more is not safer, and longer use can increase the risk of ulcers, right dorsal colitis, kidney injury, and low blood protein.

One important point for pet parents: meclofenamic acid does not work instantly. Clinical effect may take 2 to 4 days to build. If a horse seems painful despite treatment, contact your vet rather than adding another NSAID on your own.

If treatment is needed beyond the initial course, your vet may reassess hydration, appetite, manure quality, bloodwork, albumin, and whether another medication would be a better fit. Horses with foals at side, breeding animals, seniors, dehydrated horses, and horses with a history of ulcers or kidney concerns may need a different plan.

Like other NSAIDs, meclofenamic acid can cause gastrointestinal and kidney side effects, especially if the dose is too high, the course is too long, or the horse is dehydrated or medically fragile. Early warning signs of NSAID trouble in horses can include depression, reduced appetite, and a drop in blood protein. More obvious signs may include diarrhea, soft manure, weight loss, ventral edema, oral ulcers, colic signs, or worsening lethargy.

A serious complication of NSAID use in horses is right dorsal colitis, a form of large-colon injury associated with NSAID exposure. Horses may develop diarrhea, intermittent colic, poor appetite, low protein, and swelling under the belly or limbs. Gastric ulceration and kidney injury are also possible.

Call your vet promptly if your horse develops loss of appetite, mouth sores, diarrhea, dark or reduced manure, colic signs, unusual swelling, reduced drinking, or worsening depression while taking this medication. Stop giving the drug unless your vet instructs otherwise.

Risk is higher when NSAIDs are combined, overdosed, or used in horses that are dehydrated, stressed, septic, or already dealing with kidney, liver, or gastrointestinal disease. Even recommended doses can cause problems in unusually sensitive horses, so close monitoring matters.

The most important interaction concern is using meclofenamic acid with another NSAID or a corticosteroid. Combining NSAIDs such as phenylbutazone, flunixin meglumine, ketoprofen, diclofenac, meloxicam, or firocoxib can sharply increase the risk of stomach and colon injury, low protein, and kidney damage. Pairing an NSAID with steroids such as dexamethasone or prednisolone can also raise ulcer risk.

Your vet should also know about any medications or conditions that may affect kidney perfusion, hydration, protein binding, or gastrointestinal health. Horses that are dehydrated, have diarrhea, are not eating well, or are receiving other potentially kidney-stressing drugs may need a different pain-control plan.

Because meclofenamic acid is highly protein bound, your vet may be more cautious in horses with low albumin, severe systemic illness, or heavy medication use. Supplements, ulcer medications, and feed timing can also matter when building a safe plan, even if they do not create a classic drug-drug interaction.

Before starting this medication, give your vet a full list of everything your horse receives: prescription drugs, over-the-counter products, joint supplements, ulcer medications, and show medications. That helps your vet choose the safest option and avoid accidental NSAID stacking.