EPM Treatment A horse suffering from neurological symptoms caused by EPM.

FDA Approves New Dosing for EPM Treatment


The Food and Drug Administration (FDA) has approved new dosing for the first approved treatment for equine protozoal myeloencephalitis (EPM).
The FDA has approved giving a loading, or larger dose, of Marquis on the first day to begin the treatment. Marquis contains ponazuril.
EPM is a neurological disease in horses caused by Sarcocystis neurona, a parasite that invades the brain and spinal cord. When undetected or untreated, EPM can cause serious damage to the horse’s central nervous system and in some cases be fatal.
Opossums are definitive hosts for this parasite. Horses become infected with EPM through contact with opossum feces by grazing or by eating contaminated feed.
Administration of the loading dose allows Marquis concentrations to approach a steady state within 1-2 days, as opposed to eight days using the originally approved dosage regimen.
Recovery from EPM can be successful if the horse receives prompt and proper treatment. The most significant improvements are generally seen within the first four weeks.