Metronidazole for Dogs – Everything You MUST KNOW!

When it comes to bacterial infections, diarrhea, and Giardia, Veterinarians usually prescribe Metronidazole for dogs.

Metronidazole is a drug that is not approved by the FDA for use in animals. But, veterinarians have been using them successfully in dogs and cats without any harm.

In this post, we will discuss everything you need to know about this antibacterial and antiprotozoal medication. You’ll learn what this drug is used for, how to use this, when and when not to give this to your pet dog.

Let’s get into it.

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What is Metronidazole?

Metronidazole is better known by brand names such as Flagyl, Metizol, Protostat, and Metrogel.

It is an antibiotic (antibacterial and antiprotozoal) drug that is used for treating bacterial infections, diarrhea, bowel inflammations and other conditions.

This is a prescription drug meaning you must get a prescription from your vet to get your hands on one. They are available mostly in tablet form.

So, what is this Metronidazole and how does it work?

Metronidazole, being an antibiotic, is capable of fighting anaerobic bacteria and parasites.

These anaerobic bacteria can survive in places where there is less air and start causing problems. Some of those problems include liver and abdomen diseases, inflammation in the bowels, etc.

Metronidazole can block some functions in these anaerobic bacteria and parasites that eventually lead to their death.

This is how this antibacterial drug helps your dog.

Metronidazole Dosage for Dogs

You must not make decisions of your own when it comes to Metronidazole dosage for your dog.

Always stick to the dosage your vet prescribes and never skip the medicine. The dosage strictly depends on the condition that is being treated.

For a general guideline, the following are the expected dosage of Metronidazole for dogs.

For bacterial infections, the preferred dosage is between 11 to 22 mg/lb of your dog’s weight. This is to be given twice per day. For example, if your dog weighs 30 pounds, then the dosage here can range from 330mg to 660mg of Metronidazole.

For Giardia, 7 to 11 mg/lb is the usual dosage prescribed. But if there is a need, the dosage might be increased up to 29.5 mg/lb. This is to be given once in every 24 hours.

There are more conditions that can be treated with the same drug and the dosage for them will be different depending on the severity.

Remember, these are only general guidelines and are not meant to be followed without getting a go-ahead from your vet. Stick to the prescription given by your vet, and there will be no issues.

Metronidazole for Dogs: Side Effects

There are some common side effects when you give your dog Metronidazole.

These include

  • Nausea
  • Fatigue
  • Fever
  • Diarrhea
  • Vomiting
  • Lethargy
  • Weakness
  • Blood in urine
  • Disorientation and stumbling

If the tablet stays in your dog’s mouth for a long time, it can lead to excessive salivation.

There are also some harsh side effects like liver disease. In this case, the gums, eyes, and skin may turn yellow. There is also a chance for nerve damage, allergic reactions like hives, facial swelling, sudden diarrhea, shock, and seizures.

If you witness these symptoms, immediately rush to your vet and let him or her examine your dog’s condition.

Metronidazole Overdose in Dogs

Metronidazole overdose in dogs is a serious issue and should not be taken lightly.

In case of an overdose, your dog might experience tremor, seizures, depression, head tilt, anorexia, and stiffness.

Some of these are seen only in dogs that are on medication for a longer period. Though these may not seem life threatening, they take a toll on your dog’s health. So be sure not to give more than what is necessary.

Important: If you missed a dose, administer it as soon as you recall. If the time for the next dose is close, just skip it. Do not give two doses together. This is also overdose and is not safe for your dog.


Below are some common questions that are frequently asked.

Is Metronidazole safe for dogs?

We should be clear by now that this drug is not approved by FDA for use in animals.

Having said that, veterinarians have been using them without any problems for a long time. And it is only increasing in use. So, we can say that it is harmless for dogs.

But if you see any unusual side effects (possible with any medication), contact your vet and let him know.

How long does Metronidazole take to work in dogs?

Since Metronidazole is used to treat a number of conditions, we can’t tell one particular time. In some cases, the medication itself is for a long period and in some cases, not.

So, it really depends on the condition.

What are some safety guidelines for giving my dog Metronidazole?

Always talk to your vet before giving any medication to your dog.

Inform him about the medical conditions your dog is suffering from. Let him know all the medications your dog is under.

Also, Metronidazole is not recommended for dogs that are pregnant or lactating.

When not to give Metronidazole to my dog?

Do not give Metronidazole for puppies.

Do not give Metronidazole for lactating or pregnant animals.

Do not give Metronidazole if your pet has kidney or liver disease (or any other condition that might trigger an adverse reaction).

What should I do in case of an overdose?

Immediately rush to the vet. An overdose can result in tremors, stiffness, head tilt, vomiting, and other outcomes (see above).

An overdose of any medicine in dogs is a serious issue, so never delay.

We hope you got some useful information from this article. Let us know if you think there is something that hasn’t been covered. We would love to hear it from you!

Featured photo credit: KelkoNiki/depositphotos (edited)