Treatment
Click here to view the complete label and usage instructions for Marquis.
Treat EPM with confidence. Treat with Marquis.
Ponazuril, the active ingredient in Marquis, crosses the blood/brain barrier to reach the central nervous system where it kills Sarcocystis neurona,1,2 and stops parasite from inflicting further damage to the central nervous system.3
Concentrations achieved in the cerebral spinal fluid after oral dosing were as high or higher than what is required to kill 94% of the parasites in cell culture.2
Ponazuril works at the level of the ‘plastid body’ within the cell of the merozoite. Ponazuril is safe to use in horses because there is no plastid body within mammalian cells.2 It won't cause folic acid deficiency and resulting anemia/leukopenia like sulfa drugs & pyrimethamine.4 Marquis is safe to use in horses, causing few adverse effects.3
Its pre-calibrated oral dosing syringe ensures accurate delivery of each dose. Marquis is easy to administer correctly; the horse owner can give the full dose each time. Using the labeled dose of 5 mg/kg for 28 days, 60% of horses improved at least 1 grade at Day 118, of these 75% were corroborated successes by video tape assessment.3
In this Pharmacokinetic study it was demonstrated that during the 28 days of treatment at the recommended dose of 5mg/kg orally there were CSF levels of Ponazuril reaching concentrations of >0.1µg/mL when sampled at day 7. Results of subsequent weekly measurements of CSF ponazuril levels while horses continued to be treated with 5mg/kg daily suggest this to be steady state concentration. When treatment with ponazuril was discontinued, CSF levels fell below 0.1µg/ml within one week. This study supports daily treatment at 5mg/kg to maintain CSF levels of ponazuril that have been shown in-vitro to be effective against S. neurona.
What this graph demonstrates is the importance of administering the correct dose to maintain steady state and that partial dosing may result in levels of active drug in the CSF that are too low to be effective. You can see that it would be very easy to drop below steady state and allow the merozoites to continue to reproduce and potentially cause permanent damage.1
The benefits of Marquis® (15% w/w ponazuril) are numerous.
| Features | Benefits |
| Kill the parasite Sarcocystis neurona. | Stops parasite from inflicting further damage to central nervous system (CNS). |
| 94% inhibition of merozoite production in cell culture.2 | Highly effective against S. neurona. |
| Crosses the blood/brain barrier.1 | Reaches CNS, where it kills the parasite. |
| Safe to use in horses.3 | Few adverse effects.3 |
| Targets intracellular protozoan pathways not equine systems.2 | Don't have to monitor for bone marrow suppression as when using sulfa-Trimethoprin/pyrimethamine combos.4 |
| Pre-calibrated dosing syringe. | Ensures complete delivery of accurate dose. |
| Reliable oral administration. | Not dependent on feed administration. |
| Stable for 2 years when stored as directed. | Compounded drugs in suspension may have very short stability |
Click here to view the complete label and usage instructions for Marquis.
Learn more:
- Signs of EPM
- Horses at Risk
- Diagnosis
- Methods of Prevention
- Life Cycle of the Protozoa
- EPM Ongoing Research
Federal (U.S.A.) law restricts this drug to use by or on the order of
a licensed veterinarian.
For use in horses only. Do not use in horses intended for food.
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 is asymmetrical and affects the hind limbs.
The safe use of Marquis in horses used for breeding purposes, during pregnancy, or in lactating mares, has not been evaluated.
In animal safety studies, loose feces, sporadic inappetence, lost weight, and moderate edema in the uterine epithelium were observed.
- Furr, M and Kennedy, T: Cerebrospinal Fluid and Serum concentrations of Ponazuril in Horses, Veterinary Therapeutics, Vol 2, No 3, Summer 2001, pages 232-237.
- Lindsay DS, Dubey JP, Kennedy TJ Determination of the Activity of Ponazuril against Sarcocystis neurona in Cell Cultures. Vet Parasit 2000; 92: 165-169.
- Freedom of Information Summary for Marquis® (15% w/w ponazuril) Antiprotozoal Oral Paste. NADA 141-188.
- Reed S. Neurology is Not a Euphemism for Necropsy: A Review of Selected Neurologic Diseases Affecting Horses, Proceedings of the 54th Annual Convention of the AAEP, San Diego, CA December 2008 pg 78-109.
