Metronidazole For Dogs: Uses, Dosage, And Side Effects

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Metronidazole is an antibiotic prescribed by veterinarians for dogs to treat diarrhea, inflammation of the large intestine, and other bacterial and parasitic infections such as Giardia. It is also known by the brand name Flagyl. Metronidazole is not FDA approved for use in canines, but it can be prescribed by a licensed veterinarian. The drug works by disrupting the creation of DNA in bacteria and only treats infections of anaerobic pathogens, though it is often used with other antibiotics to cover other sources of infections. Follow the instructions of your veterinarian strictly when giving any medication to your dog. Here is what you should know about the uses, dosage, and side effects of metronidazole in dogs.

Uses Of Metronidazole For Dogs

Giardia lamblia is a flagellated protozoan parasite. It colonizes and reproduces in the small intestine and causes giardiasis.

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As mentioned before, metronidazole is used to treat conditions such as diarrhea and inflammation of the lower intestine when certain parasitic or bacterial infections are the cause. These include Giardia, Trichomonas and Balantidium coli. It can also be used to treat Inflammatory Bowel Disease (IBS), sepsis, oral or dental infections, bone infections, or internal abscesses. The drug is able to cross the blood-brain barrier, which makes it useful in treating central nervous system infections, as well.

Dosage Of Metronidazole For Dogs

English Bulldog dog canine pet on brown leather couch under blanket looking sad bored lonely sick tired exhausted

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The proper dosage of metronidazole for dogs depends on which condition is being treated. You should always rely on your veterinarian to give you the proper dosage for your dog. In the case of Giardia, 7 to 11 mg per pounds is often prescribed to be given every once every 24 hours, but the dosage can go as high as  29.5 mg per pound. If your dog has an infection from anaerobic bacteria, you might expect your vet to prescribe 11 to 22 mg per pound to be given twice a day.

Metronidazole tablets typically come in doses of 250 to 500 mg per pill. Your vet can give you advice on how to properly measure the dose for your dog. These pills are extended-release for humans, but dogs have a shorter digestive tract and may only partially digest the medication before passing it. Again, follow the instructions of your vet for administering it. In some cases of sepsis or if a dog’s airway is blocked, a vet may inject the drug.

Risks And Side Effects Of Metronidazole For Dogs

Scotland shepherd dog lying on a bed indoors

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Side effects of metronidazole in dogs are rare, and the drug is considered to be quite safe when administered properly. Still, dogs who are pregnant, are puppies, have a history of liver or kidney disease, suffer from neutropenia, or have seizure disorders should not be exposed if it is avoidable. Make sure your vet is aware of these conditions and any other medications your dog may be on.

Though the side effects are rare, long-term exposure heightens the risk. Common side effects of metronidazole in dogs include the following.

  • Nausea or vomiting
  • Diarrhea
  • Drooling
  • Gagging or reguritation
  • Loss of appetite
  • Lethargy or fatigue
  • Blood or darkening of urine
  • Fever

Some rare, more serious side effects that usually only occur with long-term use include low blood platelet count, liver damage, insomnia, or neurological conditions related to toxicity. Neurological symptoms might include seizures, staggering, stiffness, or strange movements and behavior. If you notice these symptoms, contact your vet right away.

With nearly all medications, there is a risk of allergic reaction that can lead to anaphylaxis, a potentially fatal condition. If you see signs of an allergic reaction such as swelling, difficulty breathing, or closing of the throat, get to an emergency vet immediately.

Have you ever treated your dog with metronidazole? Did you see results? Let us know in the comments below!