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Ornidazole

Prescription
Nitroimidazole Antiprotozoal / Antibacterial
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Formulations
3

Mechanism of action

Nitroimidazole that disrupts DNA of anaerobic organisms and protozoa after intracellular reduction. Active against Giardia, Trichomonas, Entamoeba, and anaerobic bacteria.

At a glance

Class
Nitroimidazole Antiprotozoal / Antibacterial
Schedule
Prescription
Storage
Store at room temperature, protect from light

Dosing

🐕

Dog

Used for giardiasis, anaerobic infections, and amoebic dysentery
Dose
30 mg/kg
Route
PO
Frequency
q24h
🐈

Cat

Alternative to metronidazole in cats; monitor for neurological side effects
Dose
30 mg/kg
Route
PO
Frequency
q24h

Formulations

💊

Other — 3

Strength
Strength
Strength

Storage

Store at room temperature, protect from light

Safety

Monitoring parameters

Neurological statusLiver enzymes with prolonged use

Interactions

No documented interactions.

Brands

Other markets

Ornida
Dazolic

FAQs

Frequently asked questions

What is Ornidazole?
Ornidazole is a nitroimidazole antiprotozoal / antibacterial used in pets. Nitroimidazole that disrupts DNA of anaerobic organisms and protozoa after intracellular reduction. Active against Giardia, Trichomonas, Entamoeba, and anaerobic bacteria.
What is Ornidazole used for in pets?
Ornidazole is used in veterinary medicine for: Used for giardiasis, anaerobic infections, and amoebic dysentery; Alternative to metronidazole in cats; monitor for neurological side effects.
What is the Ornidazole dose for dogs?
For dogs, Ornidazole is typically dosed as follows — Used for giardiasis, anaerobic infections, and amoebic dysentery: 30 mg/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Ornidazole dose for cats?
For cats, Ornidazole is typically dosed as follows — Alternative to metronidazole in cats; monitor for neurological side effects: 30 mg/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Ornidazole need a prescription?
Yes. Ornidazole is a prescription medication and should only be administered under veterinary supervision.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Related medicines

Other medicines in the same class (Nitroimidazole Antiprotozoal / Antibacterial).

Tinidazole
Rx
Second-generation nitroimidazole with longer half-life than metronidazole. Intracellular reduction generates reactive metabolites that damage protozoal and anaerobic bacterial DNA. Active against Giardia, Trichomonas, Entamoeba, and anaerobes.
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