405 Heron Drive Suite 200
Swedesboro, NJ 08085
Ph 800.331.8272

Ronidazole for Cats


General Drug Information and Indications
How to Give this Medication
Side Effects
Drug Interactions
Search for Available Dosage Forms 

General Drug Information and Indications

Ronidazole is most commonly used to treat a protozoal infection in cats called Tritrichomonas foetus. This protozoa is a common cause of diarrhea in cats, particularly young cats and those living in multi-cat households. The incidence of

T. foetus appears to be much more common than previously thought. In a study performed at a large cat show, more than one third of the cats were positive on fecal sample. Transmission is fecal-oral, which makes litter box hygiene particularly important even while treating symptomatic animals.

Ronidazole is closely related to the antibiotic/antiprotozoal drug metronidazole, which is a commonly used drug. Metronidazole appears to be no longer effective against Tritrichomonas, but multiple studies have shown ronidazole to have good efficacy. Like many other drugs in veterinary medicine, this drug is not FDA approved for use in animals and is not available from a veterinary pharmaceutical manufacturer. Instead, it is compounded by a specialty pharmacy. 

How to Give this Medication

Give this medication to your pet exactly as your veterinarian prescribes. If you miss giving your pet a dose of ronidazole, give the next dose as soon as you remember or, if it is close to the next scheduled dose, return to the regular schedule. Do not double dose to catch up.

Ronidazole is usually compounded in a capsule because it is very bitter tasting.

Ronidazole is possibly carcinogenic. Human contact should be minimized. You should wear gloves when handling ronidazole and wash your hands after giving your pet this medication. 

Side Effects

Be sure to discuss any side effects with your veterinarian immediately. 

The most common side effects are gastrointestinal. They include nausea, loss of appetite and vomiting.

Less common but more serious side effects are related to the nervous system. They can include weakness, loss of balance, twitching, and seizures. Usually these side effects will diminish simply by discontinuing the medication. On rare occasion, they may worsen and persist for as long as one month after the medication is discontinued.


Keep this and all drugs out of reach of children. This drug should only be given to the animal for which it was prescribed. Do not give this medication to a person. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

In order to avoid side effects, it is important to calculate the dose based on an accurate body weight. The dose rate may be further decreased in kittens.

Ronidazole has been shown to cause birth defects. It should not be used in pregnant animals. The FDA prohibits its use in animals that may enter the food chain.

Drug Interactions

Be sure to review with your veterinarian any medications or supplements your pet may be receiving.

There is very little specific information regarding drug interactions with ronidazole. The following drug interactions are extrapolated from experience with metronidazole which is a very similar drug. Drugs that may interact include: cyclosporine, systemic tacrolimus, fluorouacil, lithium, cimetidine, ketoconazole, oxytetracyclines, phenobarbital, rifampin, phenytoin, alcohol, and coumarin anti-coagulants.


If you suspect your pet or another animal was overdosed accidentally or has eaten this medication inadvertently, contact your veterinarian or the A.S.P.C.A.’s Animal Poison Control Center at 888.426.4435. Always bring the prescription container with you when you take your pet for treatment.

If you or someone else has accidentally ingested this medication call the National Capital Poison Center at 800.222.1222.


Different strengths or dosage forms of ronidazole may have different storage requirements. Read the labeling or ask your pharmacist for the storage requirements of the prescription you receive. 

The information contained on this site is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the products shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular product. You should consult your doctor about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the products to diagnose, cure or prevent disease. 

Wedgewood Pharmacy compounded veterinary preparations are not intended for use in food and food-producing animals.
Looking for Ronidazole?

We can let your veterinarian know that you are interested in our compounded Ronidazole.

Have a written prescription from your veterinarian?
Get your instant quote by chat!
About the Author

Dr. Barbara Forney is a veterinary practitioner in Chester County, Pennsylvania. She has a master's degree in animal science from the University of Delaware and graduated from the University of Pennsylvania School of Veterinary Medicine in 1982.

She began to develop her interest in client education and medical writing in 1997. Recent publications include portions of The Pill Book Guide to Medication for Your Dog and Cat, and most recently Understanding Equine Medications published by the Bloodhorse.

Dr. Forney is an FEI veterinarian and an active member of the AAEP, AVMA, and AMWA.