Ponazuril (INN), sold by the Bayer Corporation under the trade name Marquis, is a drug currently approved for the treatment of equine protozoal myeloencephalitis (EPM) in horses, caused by Sarcocystis neurona. More recently, veterinarians have been preparing a formulary version of the medication for use in small animals such as cats, dogs, and rabbits against coccidia, an intestinal parasite. Coccidia treatment is far shorter than treatment for EPM.
^MacKay, R. J.; Tanhauser, S. T.; Gillis, K. D.; Mayhew, I. G.; Kennedy, T. J. (2008). "Effect of intermittent oral administration of ponazuril on experimentalSarcocystis neuronainfection of horses". American Journal of Veterinary Research. 69 (3): 396–402. PMID18312139. doi:10.2460/ajvr.69.3.396.