MARQUIS for horses is indicated for the treatment of equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. EPM is one of the most common equine central nervous system disorders in horses. The sooner EPM is diagnosed and appropriately treated, the better the chance of recovery. 

The active ingredient in MARQUIS, ponazuril, crosses the blood brain barrier and targets the merozoite stages of the protozoa without affecting mammalian cells making it a safe choice for horses.¹ MARQUIS paste kills Sarcocystis neurona to prevent further damage to the central nervous system. 

To use a neurological exam tool, visit the Resources tab for a downloadable PDF version.

For use in animals only. Not for human use. The safe use of MARQUIS in horses used for breeding purposes; during pregnancy or in lactating mares has not been evaluated.

MARQUIS for horses is available with a prescription by a veterinarian, but can be administered by a horse owner. Administer MARQUIS at a dose of 15 mg/kg body weight as a loading dose for the first dose only. The loading dose is followed by a maintenance dose of 5 mg/kg body weight once daily for a period of 27 additional days.

To administer MARQUIS, set the dosage ring to the appropriate weight and be sure the horse's mouth contains no feed. Deposit paste on the back of the horse's tongue. To aid swallowing of paste, gently raise horse's head for a few seconds after dosing.

For use in animals only. Not for human use. Keep out of reach of children.

For use in animals only. Do not use in horses intended for human consumption. Not for human use. Keep out of the reach of children.

Store at 20-25°C (68-77°F), excursions permitted between 15-30°C (59-86°F).

Precautions: Prior to treatment, EPM should be distinguished from other diseases that may cause ataxia in horses. Injuries or lameness may also complicate the evaluation of an animal with EPM. In most instances, ataxia due to EPM in horses is asymmetrical.

Neurologic deficits, primarily ataxia, have been reported to acutely worsen during the early treatment period. In some horses, the worsening of the neurologic deficits was transient. (See Post Approval Experience Section).

Clinicians should recognize that clearance of the parasite by ponazuril may not completely resolve the clinical signs attributed to the natural progression of the disease. The prognosis for animals treated for EPM may be dependent upon the severity of disease and the duration of the infection prior to treatment.

The safe use of MARQUIS in horses used for breeding purposes; during pregnancy or in lactating mares, has not been evaluated. The safety of MARQUIS with concomitant therapies in horses has not been evaluated.