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Metronidazole for Pets

Metronidazole is a powerful antibiotic and anti-protozoal that can be used to treat a variety of ailments. It is available by prescription only, so you’ll need to consult your veterinarian if you suspect your pet may benefit from this medication. Common brand names include Flagyl, Metizol, Protostat and Metrogel.

The Petco Pharmacy fulfilled by Vetsource carries metronidazole 250 mg tablets and metronidazole 500 mg tablets. Once you have a prescription from your vet, you can submit it online and have it shipped to your door. If you don’t already have a vet, Petco’s veterinary services may be a practical option for you and your pet. 

What is metronidazole?  

Metronidazole is a powerful antibiotic that is used to treat anaerobic and protozoal infections. Anaerobic infections are caused by bacteria that thrive in areas of the infection and wounds without the free flow of oxygen—typically for gastrointestinal (GI) infections, but sometimes your veterinarian will prescribe it for deep puncture wounds or cuts in your pet’s gums or mouth. Protozoal infections primarily occur through environmental exposure, such as insect and parasite bites or by eating an infected parasite. While anaerobic infections aren’t typically passed from pets to humans, protozoal infections can be, which is one of the reasons why metronidazole for animals can be so beneficial. 

Metronidazole works by interfering with the DNA of the infecting organisms, impeding repair enzymes in the bacteria and causing them to die. Its ability to penetrate the blood barrier of bacteria and protozoa makes it ideal for treating central nervous system infections. 

What is metronidazole used to treat? 

Pet metronidazole is used primarily to treat bacterial infections and infections caused by protozoal parasites. Its unique anti-inflammatory properties make it ideal for treating inflammatory bowel disease, parasites like giardia and other conditions that are resistant to other antibiotics, including sepsis, oral damage and digestive ailments.  

Metronidazole is a human medication, and the FDA has not specifically approved metronidazole for animals yet. However, it is commonly prescribed for pets by veterinarians because of its effective treatment of diseases caused by parasites and infections. Under FDA law, veterinarians are able to prescribe medications approved for humans or other species.

How do I give my pet metronidazole?  

The antibiotic metronidazole comes in many forms, but it is often prescribed as a tablet or capsule when administered to pets. It is also sometimes turned into an oral suspension. Metronidazole cream and metronidazole gel are also available. In more serious medical situations, metronidazole can be administered intravenously by a veterinary professional. Which form a vet prescribes often depends on the site of the infection, the required dose, the root illness and the pet species. Dose guidelines for each species depend on the severity of ailment and the prescribed form of metronidazole and will be given to you by your veterinarian. If you’re unsure of the correct dosage, consult your veterinarian. 

Always consult your veterinarian before giving your pet any medication, and follow their instructions closely.  

Is metronidazole an anti-inflammatory for my dog? 

The antibiotic metronidazole does have anti-inflammatory properties, which is one reason vets use it frequently to treat Inflammatory bowel disease and inflammation of the large intestine. However, it is not used to treat hip or joint inflammation and will most likely be prescribed to treat inflammation that occurs due to infection. 

Can metronidazole treat my dog’s diarrhea?  

Metronidazole may help relieve digestive issues like diarrhea, but the answer really depends on what’s causing your dog’s intestinal distress. If your dog’s diarrhea is due to a bacterial infection or an infection from a protozoal parasite, then prescribing metronidazole may be appropriate. Determining the root cause of your dog’s gastrointestinal distress is vital in developing a treatment plan. 

Can metronidazole harm my dog? 

Any medication has the potential for harm if it is not used properly. Your veterinarian must authorize prescription medicines because their effects need to be monitored by a professional, and the dose may vary depending on the ailment and species of the patient.  

Metronidazole may not be suitable for: 

  • Young pets 
  • Pets who are pregnant or nursing 
  • Pets who have seizures 
  • Pets who have liver disease  
  • Pets who have kidney disease 
  • Pets who are allergic 

Be sure to inform your vet if your pet has any of these conditions. To avoid adverse interactions, it’s also important to give your vet a list of all other medications your pet is taking, including vitamins and supplements. 

As with most medications, metronidazole side effects in cats, dogs and other pets can occur. These may include: 

  • Diarrhea 
  • Nausea 
  • Vomiting 
  • Drooling or gagging—the medication can be bitter, triggering the gag reflex 
  • Fatigue—you may notice your pet sleeping more or feeling lethargic 
  • Loss of appetite 
  • Fever  
  • Discoloration of urine 

Signs that your pet is allergic to metronidazole—or may have been given an overdose—can include: 

  • Abnormally slow heartbeat or rapid heartbeat 
  • Tremors, stiffness or muscle spasms 
  • Seizures 
  • Abnormal twitching  
  • Dilated pupils 
  • Hives or rashes 
  • Difficulty breathing 
  • Facial swelling

Contact your veterinarian immediately if any of these metronidazole side effects occur. If your pet is on this medication for an extended period, monitor them closely as they are more likely to develop these side effects with long-term use.  

How should I store metronidazole? 

Metronidazole tablets should be stored at room temperature in a light-resistant bottle that can be tightly sealed. It’s best to keep the tablets in the container you received from the pharmacy. That way, the medication will be more secure and you’ll have easy access to the relevant prescription information. If your pet has been prescribed metronidazole as an oral suspension, it should be refrigerated. If it’s in any other form, follow the directions on the prescription or consult your veterinarian or pharmacist. As with any drug or supplement, be sure to store metronidazole in a secure area that is inaccessible to pets and children. 

After ordering metronidazole, you can continue shopping online for anything else your pet might need, whether they fly, walk, slither or crawl. We carry everything from dog vitamins and cat supplements to solutions for bird health and reptile wellness. You’re also welcome to come see us in person at your favorite neighborhood Petco Pet Care Center

Reviewed by Dr. Whitney Miller, DVM, MBA, DACVPM

As Petco’s Chief Veterinarian, Dr. Miller is the lead veterinary subject matter expert, overseeing the company’s standards of excellence in animal care and welfare, growth in pet services and much more. Dr. Miller leads Petco’s medical team, supporting over 200 full-service hospitals and mobile vaccination clinics operating in over 1,000 Petco Pet Care Centers nationwide