Metronidazole for Cats

I know there's medication in my food.
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If Kitty has a certain type of infection, your vet might prescribe metronidazole to get him well again. Whether it's his bowels, gums or skin giving him trouble, this drug can get rid of the bacteria responsible for the ailment. It doesn't taste great, so mix it carefully into food.


Metronidazole, marketed under the brand name Flagyl, is an antibiotic used to treat anaerobic infections, meaning those that don't require oxygen to grow. Unlike certain antibiotics, metronizadale is capable of crossing the patient's blood/brain barrier, so it can stop infections affecting the central nervous system. It's also rapidly absorbed by Kitty's body, getting to work right away. While it's only approved by the U.S. Food and Drug Administration for use in humans, veterinarians might prescribe it for their patients "off-label." Don't give metronidazole to pregnant or lactating animals.


If your poor Kitty suffers from colitis, you know he's in misery. He can go from one elimination extreme to the other, experiencing diarrhea and then constipation. It hurts to poop, and he often feels the need to go whether he produces anything or not. Your vet might prescribe metronidazole along with recommending dietary changes. Metronidazole damages the DNA of the infection-causing bacteria, destroying its ability to reproduce. Since most of the bacteria responsible for colitis reside in the cat's large intestine, they don't require oxygen. Your vet might also prescribe metronidazole for diarrhea of unexplained origin.

Other Uses

Your vet might prescribe oral or topical metronidazole if Kitty experiences an abscess. The tissues affected by an abscess don't receive much oxygen, so anaerobic bacteria can thrive there. Cats suffering from stomatitis, a disease of the gums, also benefit from metronidazole. Your vet might also prescribe in conjunction with another antibiotic to treat infections with a mix of aerobic and anaerobic bacteria.

Side Effects

While generally safe and effective, some cats might suffer from side effects when dosed with metronidazole. Common side effects include appetite loss, vomiting and diarrhea, lethargy, excess salivation and blood in the urine. More serious side effects might include neurological issues, liver failure and neutropenia, a drop in Kitty's white blood cell count. If your cat receives too much of the medication or is on it for a long time, he could develop metronidazole toxicity. Symptoms of toxicity include seizures, staggering, head tilting, rigidity and a slow heart beat. Stop giving Kitty the medication and take him to the vet. In rare cases, toxicity proves fatal.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.

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