Flagyl, brand of Metronidazole for dogs

Metronidazole For Dogs – All You Need To Know

With their perpetual inquisitive nature and the slightly annoying habit of chewing or licking on things, the chances of your dog picking up a bacterial infection is significantly high. Some of them can be dangerous to your dogs health and leave your dog bed ridden with constant diarrhea (especially infections of the gut or the large intestine).

Pet parents often wonder if Flagyl, which is a brand name for Metronidazole can be given to their dogs, considering that it is one of the most commonly used antibiotics for humans.

In many cases, such antibiotics are successfully used for treating infections in dogs which may further trigger this curiosity.

Nevertheless, here’s the low down on using Metronidazole for dogs.

What is Metronidazole?

Metronidazole is a multipurpose antibiotic drug that is commonly used for treating diarrhea caused due to the inflammation in the large intestine. It is also used for treating a wide range of other infections like Trichomonas, Balantidium Coli and Giardia. Depending on whether it is a bacterial infection or a protozoan one, your vet may prescribe Metronidazole along with other antibiotics as a combination of drugs.

One of the advantages of using Metronidazole in dogs is that it can effectively bypass the blood-brain barrier which is almost impossible to do with other antibiotics. This makes it a very effective and successful treatment against infections of the central nervous system, bone infections and dental infections in dogs.

However, you must be aware that Flagyl is a prescription drug for dogs. It is not approved by the FDA for use in canines. This makes it one of those drugs that you better be aware of before giving to your pet by yourself.

What Is Metronidazole Used For?

Metronidazole may be used as a standalone therapy or in combination with other antibiotics for treating a range of bacterial and parasitic infections in dogs. For example, Giardia which is a parasite that is transmitted to your dog from water, food or from soil. It can trigger constant diarrhea and occasional vomiting in your pets. Metronidazole is a very effective therapy against it.

It has excellent bioavailability in the dog’s body within just an hour of use which makes it one of the best antibiotics for your pet if prescribed by a veterinarian.

Other than this, it is used for treating Intestinal Bowel Disease, bacterial infections that can lead to sepsis and other types of dental infections.

How Metronidazole For Dogs Work?

Like most antibiotics, Metronidazole targets the bacterial cell by entering it and preventing the DNA of from forming. This stops the bacteria from replicating further in the dog’s body. When used to treat infections of the central nervous system, it is able to penetrate into damaged tissue that does not have proper oxygen supply or circulation. It targets the pathogens which are known to thrive in such anaerobic environments by preventing them from repairing and replicating.

sick dog that could use Metronidazole

Is Metronidazole Safe For My Dog?

Metronidazole is generally well tolerated in your pet’s body and is considered safe for use. However, it is a prescription drug that does come with a risk of possible side effects and there are certain conditions that it must not be used in.

For example,

  • It should not be given to puppies
  • It should not be given to pregnant dogs
  • It may not be suitable for dogs with liver disease, kidney disease, seizures and neutropenia (extremely low neutrophils in the blood)

Also, antibiotic therapy of any type should be closely monitored by your vet because there is a significant possibility of the infection recurring with a resistant strain of bacteria or pathogen. For this reason, the dosage and the treatment duration are extremely important.

Using Metronidazole for extended periods of time may cause severe side effects in your dog.

What is The Right Dosage of Metronidazole For Dogs?

The right dosage of Metronidazole for dogs will vary according to the condition being treated. For most conditions however, the normal dosage is 5mg-20mg/kg of the dog’s weight. This is divided into timed multiple doses throughout the day to keep the level of the antibiotic constant in the blood. The most important aspect of treatment with Metronidazole in dogs is the duration of therapy.

Depending on the severity of the condition, your vet may prescribe it for three to seven days.

Are There Any Side Effects That I Need to be Aware of?

Like most antibiotics, Metronidazole can cause some mild side effects as the dog’s body tries to adjust to the medication. These mild side effects will usually subside automatically in a day or two and include mild nausea or vomiting, excessive drooling, diarrhea, constant fatigue, loss of appetite, a gagging sensation and fever. If any of these symptoms continue unabated, then contact your vet immediately

In rare cases, it can also cause some very serious side effects that may be fatal for your dog if left untreated. Some of these include an allergic reaction like hives, sudden rash, difficulty in breathing, increased heartbeat, paralysis or other neurotoxic effects.

Unmonitored treatment with Metronidazole for extended time periods may also cause some very serious side effects. Some of these include sudden seizures, stiffness in the limbs, unexplained tremors and pupil dilation.

If I Missed a Dose, Can I Give a Double Dose to Make up For it?

We all forget to take our meds on time. But you must never give your dog a double dose to compensate for a missed one. The best course of action in such a scenario would be to skip that dose entirely and then adhere to the regular dosage schedule from the next dose onwards.

To ensure that you give your dog the doses on time, which is crucial in an antibiotic therapy, you can use a pill box or a reminder.


When used correctly, Metronidazole is a very useful antibiotic medication in dogs. The caveat is that you must be aware of the exact dosage, the possible risks and the exact duration of treatment. If you have any doubts, speak to your vet first before using it.