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ni-tah-ZOX-an-ide - Pronunciation guide

Brand Names

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Rx symbolNitazoxanide is used by veterinarians to treat infections caused by a variety of parasites. Nitazoxanide is a "cidal" drug. In other words, it is a drug that kills the parasite. Nitazoxanide is FDA-approved for use to treat Sarcocysitis neurona, the protozoa that cause myeloencephalitis in horses. It is thought that nitazoxanide works by disrupting a stage of the parasite's energy metabolism, causing the parasite to die.


Nitazoxanide is a drug used in horses against a variety of parasites including protozoa, Giardia, nematodes, trematodes, and some bacteria.

Dosage and Administration

Prescription medicationNitazoxanide
Method Dosage
(click row for calculator)
Concentration Period Duration
Oral (paste) 11.36 mg/lb 0.32 mg/mg Days 1 through 5 5 days
Oral (paste) 22.72 mg/lb 0.32 mg/mg Days 6 through 28 23 days


  • Federal law restricts this drug to use by or on the order of a licensed veterinarian.
  • Extra-label use of drugs in treating animals is allowable only by licensed veterinarians within the context of a valid veterinarian-client-patient relationship, and does not include drug use in treating animals by the layman (except under the supervision of a licensed veterinarian).
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your equine appears to feel better, the entire treatment plan should be completed to prevent relapse.
  • This medication may be available in forms and concentrations not noted in the above table. Always check the label and literature provided with the medication about the form and concentration and DO NOT USE the calculator if the information differs.
  • Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

This drug has a relatively high incidence of side effects. Horses being treated with the drug should be under a veterinarian's care and monitored closely. Common side effects include decreased appetite, fever, depression, increased or decreased gut sounds, diarrhea or decreased manure production, colic, laminitis, discolored urine, increased water consumption, swelling of the head or legs, and weight loss.

The most serious side effect is potentially fatal drug-related diarrhea or enterocolitis due to disruption and change in the gastrointestinal bacteria.

Horses being treated with nitazoxanide may have a treatment crisis during the first two weeks of administration. This usually involves a worsening of the neurological signs, fever, decreased appetite, and lethargy. When this occurs, the horse may need to be treated with anti-inflammatory drugs and will require close monitoring. In some cases, treatment will need to be stopped.

Adverse reactions are treated with a variety of drugs, including NSAIDs, DMSO, dexamethasone, probiotics, antibiotics, oral electrolytes, and mineral oil.


In addition to being on the lookout for a treatment crisis during the early days of the treatment, it is important to monitor the horse's weight in order to dose this drug accurately, given its relatively narrow margin of safety.

Nitazoxanide should be used with caution in animals with decreased liver or kidney function.

Horses being treated with nitazoxanide should not be subjected to additional stress such as shipping, changes in stabling, diet, or exercise routine.

The medication is packaged with specific instructions that should be followed closely.

Nitazoxanide is FDA-approved for use with horses and is a prescription drug restricted to use by or on the written or oral order of a licensed veterinarian.

It is unlikely that nitazoxanide would be used in horses that are competing, but, in all cases, it would be important to check with the individual regulatory group.


No specific drug interactions are noted in the literature.


Overdose will result in exacerbated side effects noted above.


Nitazoxanide Navbox Injection  Nitazoxanide Navbox Injection



About the Author

EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.