Metronidazole for dogs: What you need to know

Man’s best friend is really the perfect name for our sweet little pooches. We love them so much and would basically do anything to make sure our dogs are happy and healthy. So when our dogs get sick and can’t tell us what’s wrong, we rush them to the vet and go with whatever they prescribe. 

If your vet has recently prescribed your canine metronidazole and you’d like to learn more about it, we’ve gone to the veterinary medicine experts to find out everything you need to know. 

What is metronidazole?

“Metronidazole is an antibiotic medication commonly prescribed for dogs,” said Dr. Kathryn Rosalie Dench, a veterinary surgeon, adviser, and writer at GentleDog Trainers, a recognized authority in pet care. “It belongs to a class of drugs known as nitroimidazoles and is effective against a variety of bacterial and protozoal infections.”

Along with being prescribed for dogs, metronidazole, sold under the brand name Flagyl can also be used for humans, horses, and cats. Metronidazole has not been FDA approved for small animals, but numerous studies have found scientific evidence that proves it can help with various conditions.

Uses of metronidazole in dogs

Metronidazole is an antibiotic that can be used for several different reasons. 

“It is commonly used to treat gastrointestinal infections caused by certain bacteria or parasites, such as Giardia or Clostridium,” said Dr. Rosalie Dench. 

If your dog has any infections in their mouth, on their skin, or any other areas of the body, it’s also possible your veterinarian may prescribe metronidazole to treat the infection and prevent it from spreading further. 

Metronidazole has anti-inflammatory effects within the gastrointestinal system and can help with diarrhea and symptoms of inflammatory bowel disease.

Metronidazole does best with anaerobic bacteria, meaning germs that thrive without oxygen, so they do particularly well helping infections that cause diarrhea. 

Metronidazole dosage for dogs

“The proper dosage of Metronidazole for dogs depends on the type and severity of infection being treated,” said Ellen Russell, DVM, MPH, a veterinarian at The Malamute Mom. “Generally speaking, it is recommended that a dose of 5 to 10 mg per pound of body weight be administered two times daily for five to seven days.”

The dosage and length of treatment depends on the condition Metronidazole is being used to treat. Because the dose is based on the weight of the dog, small dogs will get lower doses while larger dogs will have high doses. Dr. Russell also warned pet parents, “It is important to never exceed the prescribed dosage, as this can be harmful to the dog.”

Who should not use metronidazole for dogs

There are some dogs that may not be able to take metronidazole. This includes:

• Dogs with a known sensitivity or allergy to the medication 
• Dogs with certain neurological diseases 
• Dogs that are pregnant or lactating
• Dogs on medications that are contraindicated

Side effects of metronidazole for dogs

Side effects of Metronidazole are rare in dogs and include reduced appetite and vomiting. Some dogs are more sensitive to metronidazole and can exhibit neurologic changes while taking metronidazole. These include weakness, staggering and difficulty walking. These side effects are more likely with higher doses and longer durations of treatment and should be reported to your vet immediately if noted.

Signs of metronidazole overdose in dogs

Metronidazole toxicity may occur if your dog accidentally gets too much metronidazole. Since metronidazole can pass through the blood-brain barrier, it’s possible many of these side effects may be neurological in nature. Signs of overdose may include the following symptoms:

• Reduced appetite
• Vomiting
• Disorientation
• Ataxia (Difficulty balancing and walking)
• Tremors or seizures
• Rigid body movements
• Difficulty breathing

If you notice these symptoms, it’s essential to contact your veterinary medicine professional immediately. 

Metronidazole alternatives for dogs

If your dog has had an allergic reaction to metronidazole, drug interactions, or negative reactions to it in the past, your veterinarian may instead prescribe a different antibiotic. These may also come with potential side effects.

Drug

Natural alternatives to metronidazole

If metronidazole is being used to treat gastrointestinal disease, probiotics, fiber supplements or diet changes may be used in conjunction or in place of metronidazole. If metronidazole is prescribed to treat infections outside of the gut, antibiotics may truly be essential to treatment. 

Frequently asked questions about metronidazole for dogs

What does metronidazole treat for dogs? 

Metronidazole is typically an effective treatment for parasitic infections and various bacterial infections, including gastrointestinal infections, inflammatory bowel disease, intestinal inflammation, and skin infections.

How long does it take for metronidazole to work in dogs?

Vets typically prescribe metronidazole for five to seven days. Your dog should start feeling better within a few days, but it’s essential to complete the entire course of metronidazole to ensure the infection is completely resolved. 

Can metronidazole be used long-term in dogs?

It’s not recommended for metronidazole to be used long-term as it can affect your dog’s gut health and lead to a higher risk of toxicity. It is possible your vet will extend your dog’s treatment on metronidazole if the first round did not successfully treat the infection.

Is metronidazole safe for pregnant or nursing dogs?

“It is also not recommended for use in pregnant or lactating bitches as there is risk of fetal malformations,” said Dr. Russell.

Does metronidazole help treat upset stomach in dogs?

If your dog’s stomach is upset because of a gastrointestinal infection, metronidazole will help your dog’s stomach by curing the underlying issue. However, it is not a quick remedy to soothe their stomach or stop diarrhea.

How to store metronidazole

You don’t need to do anything special to store metronidazole. It does best at room temperature while away from light and moisture—so avoid keeping it in the bathroom.