Zimeta® (dipyrone injection) for Horses

Published May 23, 2024
equine veterinarian injects a medication through a syringe into a horse's side.

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PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Zimeta® for Horses?

Zimeta® is a prescription injection administered intravenously (directly into the bloodstream) by a veterinarian for treatment of fever (elevated body temperature) in horses.

Zimeta® is the first and only, as of the date of publication, non-steroidal anti-inflammatory drug (NSAID) of the pyrazolone class that is FDA-approved for use in horses for control of fever.

Fever can be associated with many conditions and diseases in horses such as infection (viral, bacterial, fungal) and/or inflammation. The most common cause of fever in horses is respiratory disease.

Zimeta® does not cure your horse’s underlying infection or inflammatory disease but is a symptomatic treatment to help your horse feel better and recover faster from their illness.

After performing a thorough examination on your horse to identify the cause of your horse’s fever, your veterinarian will determine if Zimeta® is right for your horse.

Zimeta® Considerations for Horses

Zimeta® should not be used in horses who are hypersensitive to the active ingredient dipyrone or in horses who have previously had an allergic reaction to similar NSAID medications.

Zimeta® should be used with caution in horses with certain medical conditions, including dehydration, kidney disease, heart disease, liver disease, and in horses at risk for excessive bleeding, such as those with a bleeding stomach ulcer or bleeding gastrointestinal ulcer.

Giving Zimeta® with certain medications can result in health risks to your horse, so it is important to discuss your horse’s medications, including vitamins and supplements, and medical conditions with your veterinarian.

It is important to note that the safe use of Zimeta® has not yet been evaluated in breeding, pregnant, or lactating horses, or horses younger than three years of age at the time of this publication.

How Zimeta® Works in Horses

Dipyrone (active ingredient in Zimeta®) belongs to the pyrazolone class of non-steroidal anti-inflammatory drugs (NSAIDs).

Dipyrone works to reduce fever by acting on the part of the brain (hypothalamus) responsible for regulating body temperature.

Dipyrone also blocks a certain chemical messenger (cyclooxygenase, also known as COX) involved in some of the harmful effects of inflammation.

Zimeta® Directions for Horses

Follow the directions on the drug label or as provided by your veterinarian.

Zimeta® is given by intravenous injection, once or twice daily, at 12-hour intervals, for up to three days.

Depending on your horse’s temperature and how they are feeling, your vet will determine how many doses your horse needs and how long your horse should stay on Zimeta®.

It is important to carefully follow your vet’s instructions.

Missed a Dose?

Speak with your veterinarian about what to do if you forget to give a dose of Zimeta®. Generally, they may instruct you to give it when you remember, or if it is almost time for your horse’s next dose, to skip the missed dose and resume your normal dosing schedule. Do not give extra or double doses.

Zimeta® Side Effects for Horses

Zimeta® is typically well-tolerated in most horses. Possible side effects include:

  • Abdominal pain (colic)

  • Diarrhea

  • Decreased appetite

  • Symptoms of abnormal bleeding due to your horse’s blood taking longer than usual to clot (prolonged clotting times), including nosebleeds, small purple or red dots in the skin (petechiae), and bruising due to broken blood vessels (ecchymosis)

  • Elevated liver level (sorbitol dehydrogenase or SDH)

  • Decreased blood protein level (albumin)

  • Stomach ulcer

  • Inflamed gastrointestinal tract (reddened lining of the right dorsal colon)

Contact your veterinarian immediately if your horse is experiencing any of these symptoms. 

Human Side Effects

Zimeta® is a prescription veterinary medication not intended for use in humans.

Due to possible side effects, humans should never use medicine dispensed for their animals and animals should not be given any medicine dispensed for a human’s use.

If Zimeta® is accidentally injected into humans, it can cause a dangerously low level of a certain type of white blood cells (neutrophils).

If you accidentally inject yourself with this medication, seek immediate medical attention and call your physician or the national Poison Control Center hotline at 800-222-1222.

Call Your Vet If:

  • Severe side effects are seen (see above)

  • Your horse's condition worsens or does not improve with treatment

  • You see or suspect an overdose

  • You have additional questions or concerns about the use of Zimeta®

Zimeta® Overdose Information for Horses

Prolonged use (longer than the maximum recommended treatment duration of three days) of Zimeta® or administration of too much medication (more frequently than twice a day) can cause symptoms of an overdose such as excessive bleeding, loss of appetite, depression (lethargy), and diarrhea.

If you suspect an overdose, immediately contact your veterinarian, seek emergency veterinary care, or call an animal poison control center. Consultation fees often apply.

Pet Poison Helpline (855) 764-7661

ASPCA Animal Poison Control (888) 426-4435

Zimeta® Storage for Horses

Always confirm storage requirements by reading the prescription label.

Zimeta® should be stored at controlled room temperatures from 68 to 77 F. Protect from light. Discard 30 days after the first puncture.

Keep out of reach of children and pets.


What does Zimeta® do for horses?

Zimeta® is used to help reduce fever in horses who are ill due to a variety of infectious or inflammatory causes.

Is Zimeta® an injectable NSAID for horses?

Yes, Zimeta® is an injectable NSAID (non-steroidal anti-inflammatory drug) specifically in the pyrazolone class, and it is administered intravenously (directly into the bloodstream).

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

Molly Price, DVM


Molly Price, DVM


Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine. She...

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