MARQUIS®, the first approved treatment for equine protozoal myeloencephalitis (EPM)
Treat EPM with confidence. MARQUIS is FDA-approved.
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 the parasite from inflicting further damage to the central nervous system. Concentrations achieved in the CSF at steady state were shown to kill 94% of merozoites in cell culture.2
MARQUIS is easy to administer and safe when used as directed.
Anatomy of Sarcocystis Neurona
(Ponazuril works at the level of the 'plastid body' within the cell of the merozoite. Ponazuril works by disrupting the mitochondria and energy metabolism, amino acid and fatty acid metabolism, and electron transport.4 This affects the ability of the organism to reproduce. Ponazuril is very safe to use in mammals because there is no plastid body within mammalian cells. It won't cause folic acid deficiency and resulting anemia/leucopenia like sulfa drugs & pyrimethamine.)5
MARQUIS is safe to use in horses, causing few adverse effects.5
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.6
In this Pharmocokinetic 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 >0.1ug/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 0.1mcg/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 correct dosing in maintaining 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
In animal safety studies, loose feces, sporadic inappetence, lost weight, and moderate edema in the uterine epithelium were observed.