Metronidazole for Cats With Diarrhea

María Besteiros
By María Besteiros, Expert veterinary assistant and canine/feline hairdresser.. July 13, 2020
Metronidazole for Cats With Diarrhea

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Metronidazole (brand name is Flagyl) is a drug used for certain bacterial and protozoal infections, such as diarrhea and other intestinal issues. If your cat has some intestinal health problems and your veterinarian has prescribed them with metronidazole, keep reading this article!

In this AnimalWised article, we will go through everything you need to know about metronidazole for cats with diarrhea, and its other uses. We include information about its dosage, different uses, side effects, interactions with other drugs and more.


  1. What is metronidazole for cats?
  2. What is metronidazole for cats used for?
  3. Metronidazole dosage for cats
  4. Contraindications of metronidazole for cats
  5. Metronidazole side effects in cats
  6. How to store metronidazole for cats

What is metronidazole for cats?

Metronidazole is an antibacterial and antiprotozoal drug used to eliminate certain infections, such as those caused by Giardia and Trichomonas. Learn more in our article about giardia in cats. Metronidazole is often used for cats with diarrhea and other intestinal problems.

The brand name for metronidazole for cats is Flagyl. This medicine can be administered orally. The ideal concentration is reached in about one hour. After 24 hours of its administration, it will be excreted in the cat's urine. It's also marketed in a certain tablet design that allows you to choose the correct one according to your veterinarian's prescription. To be more precise, these tablets have two lines that allow you to divide it into 2-4 equal parts.

You can also choose metronidazole in syrup form or injection. In either of these cases, it will be administered directly by the vet. However, this form of administration is usually for cats that have more serious health issues. Some of them even need to be hospitalised.

Metronidazole for Cats With Diarrhea - What is metronidazole for cats?
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What is metronidazole for cats used for?

Above all, metronidazole is used to treat infections in the gastrointestinal tract, such as those caused by Giardias, Trichomonas or Clostridium. In other words, metronidazole is most commonly used against diarrhea and other intestinal issues in cats. It can also be used against bacterial infections of the urinary system, mouth, throat or skin. As long as the bacteria is sensitive to metronidazole.

It's important to not that this medicine is not effective against any intestinal pathogens. Your veterinarian will need to analyse the bacteria and its cause to know if this medicine is for your cat. They will also need to take into account any other drugs your cat is taking, their weight and overall health.This is why it's so important to trust your veterinarian and follow their precise instructions.

Metronidazole dosage for cats

The dose of metronidazole for cats has to be prescribed by the vet. To give an example, in order to eliminate giardiasis cysts, vets will recommend 25 mg per kg of your cat's weight, administered orally twice a day for a week. Or, 50 mg if the dose is given in a single dose. It should not be administered less than five days.

On the other hand, the syrup is offered at the rate of 1 ml per kg of weight, twice a day and between 7-10 days. As always, the veterinarian may decide to modify the administration schedule depending on the circumstances and the evolution of your cat's recovery.

It is very important to weigh your cat in order for your vet to choose the correct dosage. Otherwise, the drug may not be as effective as it should be, or, on the other side, your cat may overdose. In the same way, it is essential that, once the duration of the treatment has been established, we follow it to the end, even if the cat improves sooner. Withdrawing the medication earlier than prescribed can lead to a relapse, in addition to promoting bacterial resistance.

Contraindications of metronidazole for cats

Metronidazole cannot be given to cats with liver or kidney problems or those who have previously had an allergic reaction to this drug. In addition, its use is not recommended for cats that are in the gestation period, since the studies carried out so far have been contradictory. In addition, as it has been proven that metronidazole is excreted in breast milk, its use in cats while breastfeeding is not recommended either.

When it comes to other drug interactions, there are a couple that may negatively interact with metronidazole. These include certain chemotherapy drugs, gastroprotectants, cyclosporine, phenobarbital, phytoin, and warafarin. This is why it's very important to let your veterinarian know if your cat is taking any other medications, this includes vitamins, supplement or even herbal therapies.

It's very important that your veterinarian knows everything they need to know before choosing the correct medication for your cat's condition.

Metronidazole for Cats With Diarrhea - Contraindications of metronidazole for cats

Metronidazole side effects in cats

There is always a small chance that your cat will experience certain side effects of metronidazole. These may include vomiting, liver and neurological disorders (such as lack of coordination or a decrease in the number of neutrophils, a type of white blood cells). If you notice your cat experiencing any of these symptoms or any other abnormalities, you must notify their veterinarian as soon as possible.

Neurological problems are more likely to arise when treatment is prolonged or the dose exceeds the recommended one. In this case, you should immediately go to the vet, who will have to interrupt the treatment and prescribe other drugs for the symptoms manifested by the cat.

How to store metronidazole for cats

Metronidazole tablets and capsules should be stored in a tightly sealed container at a temperature below below 30°C (86°F). Remember to always keep them away from the sunlight. A cabinet or drawer is a great option.

For the liquid formulations, these should be stored in the refrigerator. However, if your vet has made a special formulation, it's best to ask them how to store it and follow the instructions provided.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Metronidazole for Cats With Diarrhea, we recommend you visit our Medicine category.

  • Scorza and Lappin. (2003). Metronidazole for the treatment of feline giardiasis . ACVIM Forum.

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Metronidazole for Cats With Diarrhea