Ponazuril for Dogs and Cats
Vet-reviewed by Dr. Pippa Elliott, BVMS MRCVS ·
What is Ponazuril for Dogs and Cats
Overview
Ponazuril belongs to the triazinetrione class of antiprotozoal drugs. It is the active metabolite of toltrazuril, also known as toltrazuril sulfone, and is formulated as a 15 percent paste for equine use (Marquis Paste).
Veterinarians commonly use it off-label for treating intestinal coccidiosis in dogs and cats, especially in shelters, breeding facilities, and rescue environments where infection spreads easily. It is preferred for its ability to kill protozoa directly rather than merely slowing their growth.
Explore more parasite-control medications in our Parasites section.
What Is Ponazuril for Dogs and Cats Used For
| Condition | Notes |
|---|---|
| Coccidiosis (Cystoisospora spp.) | Primary use in dogs and cats. |
| Toxoplasma infections | Used off-label in cats. |
| Neospora caninum | Used as part of treatment protocols. |
| Shelter outbreak control | Often used during intake or as prophylaxis. |
| High-load infections | Helps reduce morbidity and mortality in young animals. |
How Ponazuril for Dogs and Cats Works
Ponazuril disrupts the intracellular development of protozoal parasites by interfering with essential biochemical pathways. It damages multiple organelles within the parasite, including structures critical for energy production and replication. This results in disruption of the parasite lifecycle and eventual elimination.
Drug Facts
Ponazuril is a broad-spectrum antiprotozoal drug used off-label in dogs and cats. It is best known for its effectiveness against coccidia.
Common Brands
Marquis®
Drug Class
Antiprotozoal (triazinetrione)
Substance Classification
Not a controlled medication
Generic Status
No true generic; compounded forms used
Availability
Prescription
Ponazuril for Dogs and Cats Dosage Forms
Ponazuril is marketed as Marquis Paste (15 percent) for horses. To use it in dogs and cats, veterinarians dilute the paste to create oral suspensions at workable concentrations.
Diluted Oral Suspension (Compounded)
| Qty/Size | Price as low as | Price per unit |
|---|---|---|
| 15 mL | $28.00 | $1.86 |
| 30 mL | $45.00 | $1.50 |
| 60 mL | $80.00 | $1.33 |
Typical Dosing For Ponazuril for Dogs and Cats
Ponazuril dosing varies based on species, severity, and protocol.
Oral Dosing
| Group | Typical Dose | Notes |
|---|---|---|
| Dogs (Standard efficacy study) | 50 mg/kg every 24 hrs × 3 days | Produced 92.9 percent oocyst clearance. |
| Dogs (Shelter protocol) | 1 mL per 4.5 kg (~30 mg/kg) | Repeat in 10 days. |
| Cats (Standard efficacy study) | 50 mg/kg × 3 days | 87.5 percent clearance by Day 8. |
| Cats (General use) | 15–30 mg/kg | Commonly used. |
Risks and Warnings for Ponazuril for Dogs and Cats
Ponazuril is generally very well tolerated, even at high doses. Most side effects are mild and temporary.
Common Side Effects (All Species)
- Vomiting
- Diarrhea
Dogs
- Vomiting or diarrhea may occur, especially without food.
- Rare liver enzyme elevations with long-term use.
- Possible ocular issues like keratoconjunctivitis sicca (KCS) in susceptible breeds.
Cats
- Occasional vomiting or diarrhea.
- Rare mild neurological signs (tremors, incoordination).
Overdose Safety
- Cats: No side effects at 50 mg/kg single dose.
- Puppies: No adverse effects at 10× overdose over three days.
- Pregnant/lactating animals: Safety unknown.
Ponazuril for Dogs and Cats Warnings and Precautions
Use Ponazuril carefully and follow veterinary instruction:
- Wear gloves when handling the medication.
- Avoid skin contact with diluted or undiluted paste.
- Shake diluted solutions thoroughly before dosing.
- Do not use past the 30-day discard period.
- Use caution in pregnant or nursing animals due to lack of studies.
- Monitor pets for GI or neurological symptoms and notify your vet if they occur.
Disclaimer: This information is for educational purposes only and should not replace professional veterinary advice. Always consult your veterinarian before using or combining any medications for your pet.
Frequently Asked Questions (FAQ)
What does Ponazuril treat in dogs and cats?
Ponazuril treats protozoal infections, especially coccidia, and is also used for
Toxoplasma
and
Neospora
infections.
How quickly does Ponazuril work?
Improvement is often seen within a few days, with significant oocyst reduction by Day 3–8 depending on species.
Is Ponazuril safe for young pets?
Yes. Studies show excellent tolerance even in very young puppies and kittens.
Why does Ponazuril need dilution?
Because Marquis Paste is made for horses; it must be diluted to create safe doses for small animals.
Can Ponazuril be used preventively?
Yes. Many shelters use it prophylactically during intake to prevent outbreaks.
Related Medications and Supplements
Dogs being treated for coccidia infections may require additional antiparasitic medications to fully eliminate the parasite or address mixed gastrointestinal infections. These related treatments are commonly used alongside Ponazuril.
- Toltrazuril - anticoccidial medication closely related to ponazuril, used for coccidia management
- Pyrantel pamoate - dewormer that treats roundworms and hookworms often found alongside protozoal infections
- Praziquantel - antiparasitic treatment for tapeworms that may be used when gastrointestinal parasites coexist
- Metronidazole - antimicrobial medication sometimes used for secondary GI inflammation or diarrhea
- Sucralfate - stomach protectant that helps soothe GI irritation during parasite recovery
References
- Bayer Limited, Animal Health Division (2010), Baycox 2.5% Oral Solution - Summary of Product Characteristics, Marketing Authorization Number VPA 10021/019/001.
- Canine Health Center [n.d.], ‘Toltrazuril vs Albon: The Ultimate Guide to Coccidia Treatment in Dogs’, Canine Health Center. Available at: http://caninehealthcenter.com/en/blog/coccidiosis-treatment-with-toltrazuril/
- Daugschies, A., Mundt, H.C. & Letkova, V. (2000), ‘Toltrazuril treatment of cystoisosporosis in dogs under experimental and field conditions’, Parasitology Research, 86(10), pp. 797–799. Available at: https://doi.org/10.1007/s004360000217; PMID: 11068811.
- Hirose, K., Takashima, K., Yamane, T. & Yamane, Y. (2016), ‘Effectiveness of Toltrazuril for Coccidiosis in Cats’, Journal of Animal Clinical Medicine, 25(1), pp. 12–15. Available at: https://doi.org/10.11252/dobutsurinshoigaku.25.12.
- Ibarra-Velarde, F., Vera-Montenegro, Y., Saldaña-Hernández, N. & Ochoa-Galván, P. (2014), ‘Comparison of the Efficacy of Two Commercial Coccidicidal Compounds on Experimentally Infected Dogs’, Pharmacology & Pharmacy, 5, pp. 1163–1170. Available at: http://dx.doi.org/10.4236/pp.2014.513127.
- Pasa, S., Voyvoda, H., Karagenc, T., Atasoy, A. & Gazyagci, S. (2011), ‘Failure of combination therapy with imidocarb dipropionate and toltrazuril to clear Hepatozoon canis infection in dogs’, Parasitology Research, 109(3), pp. 919–926. Available at: https://doi.org/10.1007/s00436-011-2334-3; PMID: 21472405.
- Petry, G., Kruedewagen, E., Kampkoetter, A. & Krieger, K. (2011), ‘Efficacy of Emodepside/Toltrazuril Suspension (Procox® Oral Suspension for Dogs) against Mixed Experimental Isospora felis/ Isospora rivolta Infection in Cats’, Parasitology Research, 109, pp. S29–S36. Available at: 10.1007/s00436-011-2400-x.
- Price, M. & Fung, C. (2023), ‘Toltrazuril for Dogs and Cats’, PetMD, 15 September.
- Rauscher, B.A., Schäfer-Somi, S., Ehling-Schulz, M., Möstl, K., Handl, S., Hinney, B., Spergser, J. & Schaper, R. (2013), ‘Control of Canine Endoparasites, Especially Isospora spp., with Procox® in Naturally Infected Puppies: Parasitological, Bacteriological and Health Parameters’, Open Journal of Veterinary Medicine, 3(2), pp. 121–130. Available at: http://dx.doi.org/10.4236/ojvm.2013.32020.
Editor
The Webvet Editorial Team is a collective of seasoned pet-care journalists, veterinary content specialists, and industry editors dedicated to delivering accurate, trustworthy, and compassionate pet health information. With decades of combined experience across veterinary reporting, pet wellness education, and consumer product research, our team works closely with veterinarians and certified pet experts to ensure every article is both evidence-based and easy to understand.
Veterinarian · BVMS MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty Puggle named Poggle, 3 cats and a bearded dragon.
