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Get the Scoop on EPM Recovery


EPM. These three little letters can be scary to hear. Fortunately, if your horse is diagnosed with EPM—technically known as equine protozoal myeloencephalitis—the disease can be safely, easily and effectively treated with Protazil® (1.56% diclazuril) Antiprotozoal Pellets from Merck Animal Health

Protazil is the only alfalfa-based top dress that’s FDA-approved to treat EPM. It is well accepted by horses without mess or fuss, so treatment is as easy as scooping the prescribed amount onto your horse’s feed.

EPM is a neurologic disease horses contract from drinking water or eating feed contaminated with opossum scat. Because EPM is a progressive disease, starting treatment early is crucial. If left untreated, it can cause lasting damage to your horse’s central nervous system (brain and spinal cord). That’s why Merck Animal Health developed Protazil to work fast, starting within 12 hours. No loading dose is needed.1

“Protazil is very safe, it works, it’s cost-effective and it’s super easy to give,” says Dr. Jennifer Groon with Feiner Equine.

To catch EPM early, contact your veterinarian immediately if your horse exhibits any of these neurological signs:

  • Gait abnormalities
  • Ataxia (incoordination)
  • Stumbling
  • Muscle atrophy
  • Weakness
  • Depression
  • Inability to chew or swallow
  • Head tilt or ear droop
  • Behavior change
  • Blindness
  • Seizures

If your horse is diagnosed with EPM, ask your veterinarian about treatment with Protazil pellets. The sooner you treat the disease with an FDA-approved product the better the horse’s chance of recovery. In fact, horses treated with an anticoccidial drug, like Protazil, are 10 times more likely to improve than untreated horses.2

Unconditional commitment to horse health


To continue advancing understanding of EPM, Merck Animal Health is continuously investing in new research to study the disease and its treatment. This includes a partnership with the University of Kentucky’s Maxwell H. Gluck Equine Research Center to support graduate student research. Through the Merck Equine Research Fellowship, Izabela De Assis Rocha, BVM, PhD candidate, is studying diclazuril (the active ingredient in Protazil) and its effect on Sarcocystis neurona, a causative agent for EPM.

Supporting ongoing research into equine health issues like EPM and developing cutting-edge products like Protazil are just two components of the Merck Animal Health Unconditional commitment to the horse and those who care for them. For more information on EPM, see this quick facts sheet.

IMPORTANT SAFETY INFORMATION: PROTAZIL® is contraindicated in horses with known hypersensitivity to diclazuril. The safety of Protazil in horses used for breeding purposes, during pregnancy, or in lactating mares, and use with concomitant therapies in horses has not been evaluated. Do not use in horses intended for human consumption. Not for human use. For complete safety information, refer to the product label.

  1. Hunyadi L, Papich MG, Pusterla N. Pharmacokinetics of a low dose and FDA labeled dose of diclazuril administered orally as a pelleted top dressing in adult horses. J of Vet Pharmacology and Therapeutics (accepted) 2014, doi: 10.111/jvp.12176. The correlation between pharmacokinetic data and clinical effectiveness is unknown.
  2. Reed SM, et al. Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment and Prevention. J Vet Intern Med 2016;30:491–502.
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