Metronidazole Killed My Dog

Metronidazole is an antibiotic that is used to treat gastrointestinal problems. Metronidazole (or Flagyl®) has been given FDA approval for human use but is yet to clear for animal use. Nevertheless, veterinarians can lawfully prescribe several human medications for use in animals in certain conditions, and it is widely used in the veterinary field. So, what may have caused your dog to die after receiving metronidazole, then?

This article will discuss everything you need to know about metronidazole.

What is Metronidazole Used for in Dogs?

Dogs are usually given metronidazole as an antibiotic for diarrhea. It can also be used to treat inflammation of the large intestine, protozoal infections including Giardia and Trichomonas, and problems related to Inflammatory Bowel Disease(IBD)

Veterinary clinics are increasingly using metronidazole as a standard treatment for various diseases outside the gastrointestinal system. Bone infections, internal abscesses, and oral and dental infections have all been treated with metronidazole. Metronidazole has also been used to treat central nervous system infections since it can penetrate the blood-brain barrier.

How Does Metronidazole Work?

Metronidazole functions by killing and inhibiting the synthesis of DNA in infectious organisms. There is typically poor oxygen circulation within the tissues when they sustain injury from inflammation, infection, or any other cause. Only specific bacteria that don’t need oxygen can survive in this situation.

Metronidazole killed my dog

Some of the reasons that can make metronidazole kill a dog include the following;


Metronidazole is a strong antibiotic that is used to treat anti-bacterial infections. However, overdosing on your dog with metronidazole can be fatal and lead to death.

Interactions with other medications

Given that some drugs may interact with metronidazole and result in negative side effects, informing your veterinarian about any additional medications your dog is receiving is crucial.  

Underlying health condition

A dog with undetected health problems like liver and kidney issues is more prone to metronidazole adverse effects than other dogs.

Improper Usage

When administering metronidazole to your dog, it’s critical to follow the dosage and administration guidelines carefully. Incorrect drug administration might result in serious side effects and even death. 

Allergic reaction

Some dogs may be extremely allergic to specific drug chemicals, which might cause an allergic reaction. 

How to Give Metronidazole To Dogs

Like all antibiotics, they frequently have an impact on the gastrointestinal tract. However, when given to dogs with food, they can lessen the impact. Therefore, it is advisable to give metronidazole with food to dogs.  

This serves to conceal the pill from our incredibly smart animal friends and protect the stomach lining while the medication is being digested.

Missed a Dose?

Metronidazole doses should be administered as soon as you remember. However, if the next dose is approaching, skip the missed one and return to your regular dosing plan. Give no additional or double dosages.

Metronidazole Dosage For Dogs

Depending on the disease being treated, a different metronidazole dosage for dogs will be prescribed. Typically, a veterinarian will prescribe between 7 and 11 milligrams (mg) per pound and up to 22 mg per pound for more serious infections.

Metronidazole Overdose Information

Metronidazole overdoses can result in nausea, vomiting, loss of appetite, and potentially fatal neurologic symptoms like seizures. Emergency care is highly required for overdoses to reduce drug absorption and neurologic side effects. Contact an animal poison control hotline or seek emergency veterinary care immediately if you suspect an overdose.

Guidelines for Safe Use Of Metronidazole

 Even though metronidazole is considered very safe, it should not be given to young puppies or expectant mothers, and it should be carefully considered before being given to nursing dogs. In addition, pets with kidney, liver, neutropenia (low white blood cell count), or epilepsy issues cannot benefit from it either.

It’s best to consult your veterinarian before giving your pet any medication.  

Inform the vet of any additional medications your dog is taking and any underlying health issues.

Use caution when using the medication for a lengthy period because side effects are more likely to occur.

If you are giving your dog metronidazole to treat diarrhea, make sure to give the dog enough fresh water to avoid dehydration.

Metronidazole Storage

The recommended storage range for metronidazole is 59°F to 77°F. Always check the label to validate the storage requirements.

Keep the container tightly shut to shield it from light and moisture.

Medication that has been compounded should be stored in accordance with the compounding pharmacy’s label.

Keep out of children’s and animals’ reach.

How many days should I give metronidazole to my dog?

The infection’s severity will help determine the number of days a dog will take metronidazole. 

Dogs typically take metronidazole for a minimum of 7 to 10 days. Depending on the dog’s response to treatment and the severity of the illness, treatment may occasionally need to be prolonged for several weeks. Even if your dog seems to be feeling better, you should continue to provide the medication according to your veterinarian’s advice for the recommended treatment period. This is because abruptly quitting the drug can cause the infection to recur.

To ensure that the infection is completely cured and to prevent antibiotic resistance, give your dog the full course of metronidazole that your veterinarian has advised. 

Metronidazole Side Effects on Dogs

Most dogs react positively to metronidazole with little to no negative effect. Stop providing metronidazole to your dog if they have any negative side effects and speak with your vet for more information.

Among the metronidazole side effects in dogs are:

  • Reduced appetite
  • Vomiting
  • Salivating excessively
  • Stomatitis (inflammation of the mouth)  
  • Candida overgrowth
  • Hepatotoxicity (liver illness) 
  • Anorexia
  • Changes in urination
  • Neurologic changes

Reactions To Other Drugs and Medications

Due to the possibility of negative responses, metronidazole should be administered to dogs receiving specific drugs with caution. Medication interactions with metronidazole include:

  • Barbiturates
  • Phenytoin
  • Warfarin
  • Cimetidine
  • Lithium
  • Terfenadine
  • Astemizole
  • Vitamin K antagonists

 Before beginning metronidazole treatment for your dog, consult your vet if they are taking any of the drugs mentioned above. To lessen the chance of an adverse response, your veterinarian may advise starting with a lower dose of metronidazole or switching to another drug.

Symptoms of Metronidazole (Flagyl) Toxicity in Dogs

Depending on the dosage and the underlying cause, metronidazole toxicity symptoms may manifest immediately, after a few hours, or even after 7–10 days. Although an allergic reaction is typically quick, your dog may not begin to exhibit any symptoms of problems for several days if an accidental overdose occurs. Signs of metronidazole toxicity include;

  • Drooling
  • Gagging
  • Smacking lips
  • Pawing at the mouth
  • Cough
  • Sneezing
  • Runny nose
  • Extreme lethargy
  • Weakness
  • Nausea
  • Vomiting
  • Appetite loss
  • Fever
  • Chills
  • Hives
  • Dizziness
  • Confusion
  • Agitation
  • Sores inside the mouth or on the lips
  • Watery or bloody diarrhea
  • Loss of balance or coordination
  • Swelling of the face, lips, tongue, or throat
  • Inability to walk
  • Irregular heart rate
  • Difficulty breathing
  • Liver damage (yellowing of the eyes and skin, appetite loss, fever, diarrhea, fluid retention)
  • Seizures
  • Death

Alternative To Metronidazole For Dogs


Dogs with serious infections, especially those resistant to other antibiotics, are usually treated with this antibiotic. It is normally well tolerated and, in some circumstances, a good substitute for metronidazole.


Clindamycin is an antibiotic that can be used to treat infections in dogs and is effective against various bacteria. It is normally well tolerated and, in some circumstances, a viable substitute for metronidazole.


This antibiotic is commonly used to treat various illnesses in dogs and may be a suitable alternative to metronidazole in some circumstances. Although it is normally tolerated well, some dogs may develop negative side effects like nausea or diarrhea.


This drug is used to treat the same kinds of infections as metronidazole. It is normally well-tolerated by dogs and could be a suitable alternative if your dog has problems with metronidazole side effects.


This drug may be useful for treating dogs’ digestive problems and heart and renal diseases. It functions by increasing urine production and can aid in clearing the body of dangerous bacteria.


Pumpkin is a natural source of fiber that can facilitate better bowel movements and may be useful in easing the symptoms of digestive problems. Small amounts of it can be included in your dog’s meal.

Bone Broth

Bone broth is a natural source of nutrients that can assist to repair the lining of the digestive tract and may be useful in easing the symptoms of digestive problems. Most of the time, dogs tolerate it well and can be given treats or food containing modest amounts.

Digestive enzymes

These supplements have enzymes that aid in the breakdown of food in the digestive tract and may be useful in easing the symptoms of digestive problems. They are usually sold as powder or capsules.


These supplements have non-digestible fibers that support the growth of healthy gut bacteria and may lessen digestive problems’ symptoms. They are commonly sold as powder or capsules.


These supplements include healthy bacteria in them that may assist in balancing the microflora in the gut and lessen symptoms of digestive problems. Probiotics come in many forms for dogs, including capsules, powders, and treats.

Inappropriate Uses of Metronidazole

Since previous studies have shown that metronidazole is effective against certain causes of diarrhea in dogs, it is now frequently prescribed by vets for diarrhea in general. The issue is that there isn’t much scientific proof that any of the conditions metronidazole is prescribed for are helped by it. Despite this, metronidazole has surpassed all other antimicrobial drugs as the most often prescribed treatment for acute canine diarrhea. According to research, there are three typical circumstances where metronidazole has been shown to be inappropriate. They include;

Inflammatory Bowel Disease (IBD)

Metronidazole is widely used for diarrhea in dogs with IBD and other chronic gastrointestinal disorders, often in conjunction with the steroid prednisone, because it benefits Crohn’s disease in humans. However, the combination of prednisone and metronidazole is no more effective for treating IBD than prednisone alone, according to research published in 2010.

Acute Diarrhea

Metronidazole has historically been successful against diarrhea-causing organisms like Giardia and C. diff; thus, veterinarians are increasingly using it to treat diarrhea caused by other causes. However, there is limited proof that it relieves acute nonspecific diarrhea (diarrhea with no known cause), which accounts for most instances of diarrhea in cats and dogs.

There is some evidence that metronidazole shortens the time it takes for acute diarrhea to resolve in the veterinary field. However, research on dogs revealed that this reduction only lasted a few days. Additionally, most canine diarrhea cases cure within a few days “independent of treatment,” as the authors noted.

Giardia Infection

The protozoan parasites Giardia and Trichomonas, known to cause diarrhea in cats and dogs, were formerly treated with metronidazole. However, metronidazole is no longer effective enough to cure protozoal infections on its own because both of these organisms have become resistant to it over time.


Does Metronidazole Make Dogs Sleepy?

Metronidazole interacts with bacterial DNA but also has an anti-inflammatory effect, particularly in the digestive system. This might be connected to immune system suppression in some way. Like when we people take an antihistamine, some dogs may experience sleepiness.

It is not cause for concern and is a fairly common side effect as long as it is not extreme fatigue or the dog becomes entirely unresponsive.

How long does metronidazole take to work on dogs?

Most dogs will require at least five to seven days of treatment with this drug. However, some dogs will require treatment for a month or longer, depending on the problem. Your veterinarian will decide on the right dosage and course of action for your dog based on weight and the condition being treated.

Where to Buy Metronidazole For Canines

Dogs can get metronidazole on a prescription. This indicates that only a veterinarian can prescribe it (or a human doctor for humans). It can only be purchased and sold at pharmacies. Don’t purchase metronidazole if you ever see it for sale somewhere else.

Owners should never purchase antibiotics from independent sellers due to the strict international regulations governing their sale and administration. The drug’s efficacy, safety, and purity cannot be guaranteed if it is bought privately. It could result in problems ranging from the medication not having the desired effect to life-threatening health conditions.


Every dog is unique and responds differently to medicine. Metronidazole has been used for long by veterinarians and has worked well for some dogs. However, it has led to side effects for some dogs in sometimes fatalities.

It is important to discuss with your vet before administering any drug to your pet and follow the prescription to the latter. Additionally, you should notify your vet immediately if you notice some adverse effects of a drug on your pet.

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