MARQUIS (15% w/w ponazuril) Antiprotozoal Oral Paste is the first treatment approved by the FDA for equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. EPM is a serious neurologic disease that can lead to muscle loss, ataxia, and incoordination if untreated. The active ingredient, ponazuril, is a triazine-class antiprotozoal that crosses the blood-brain barrier to kill parasites in the central nervous system and prevents further neurologic damage. The easy-to-use oral paste comes in a calibrated syringe for accurate dosing and features a loading-dose and maintenance protocol that allows for rapid therapeutic levels. When used as directed, MARQUIS provides safe and effective parasite clearance in four weeks.

What Its For

For horses diagnosed with EPM caused by Sarcocystis neurona. Including incoordination, muscle atrophy, weakness, or difficulty swallowing, as confirmed by veterinary testing for Sarcocystis neurona. MARQUIS is safe for use in adult horses when administered according to label directions. The safety of this product has not been determined in foals under one year of age, breeding stallions, or pregnant mares.

How It Works

MARQUIS contains ponazuril, a triazine-class antiprotozoal that targets the merozoite stages of Sarcocystis neurona. The compound interferes with protozoal metabolic pathways leading to parasite death. Because it crosses the blood-brain barrier, it can act within the central nervous system to reduce further damage.

Cautions/Precautions

Horses may experience loose stools, mild colic, or inappetence, oral ulcers or hives during treatment.
Neurologic signs may temporarily intensify as parasites die off; monitor closely and contact a veterinarian if symptoms worsen significantly.
Use only under veterinary supervision.
Do not administer to horses with known hypersensitivity to ponazuril or other triazine compounds.
The safety of concurrent use with other antiparasitic or neurologic medications has not been evaluated.

Storage

Store at 15-30°C (59-86°F). Excursions permitted within this range. Do not freeze. Protect from direct sunlight and keep the syringe cap tightly closed when not in use. Use entire contents within the treatment course period; discard partially used syringes per veterinary disposal guidelines.

Active Ingredients

Ponazuril (15% w/w) per gram of oral paste.

How Its Sold

MARQUIS (15% w/w ponazuril) Oral Paste is supplied in a 127-gram calibrated dosing syringe, with each syringe containing enough product to treat one 1,200 lb (545 kg) horse for 7 days. MARQUIS is sold as individual syringes or a pack of 4.

Additional Information

For product or technical support, contact Boehringer Ingelheim Animal Health USA Inc. 1.888.637.4251 (opt. 2) ©2025 Boehringer Ingelheim Animal Health USA Inc. All rights reserved. MARQUIS is a registered trademark of Boehringer Ingelheim Animal Health USA Inc. All other trademarks are property of their respective owners. ©2025 Boehringer Ingelheim Animal Health USA Inc., Duluth, GA. All rights reserved. US-EQU-0397-2025.

References

1. Freedom of Information Summary - NADA 141-188, FDA, 2001. 2. Boehringer Ingelheim Animal Health, Marquis Product Label Information, 2023.