Metronidazole is a commonantibiotic medication that may be used to treat diarrhea, inflammatory bowel disease, and infestations of Trichomonas and Giardia in dogs, which are both common parasitic infestations. Often, due to parasitic resistance to this medication, other drugs may be used along with metronidazole. You should always use the medication according to your dog’s veterinarian’s directions and should not stop the medication early, even if signs of the illness resolve.

What Is Metronidazole?

Metronidazole, also known by the brand name Flagyl, is an antibiotic that is used in both humans and animals to treat conditions of the colon—your dog has probably been prescribed this medication during a bout with diarrhea. This drug has both antibacterial and antiprotozoal effects and may be used to treat anaerobic bacterial infections as well as those caused by certain protozoa.

Dosage Forms of Metronidazole

Commercially, metronidazole is available as a capsule, tablet, and liquid suspension. The medication has a rather bitter taste and may be challenging to administer to pets. Metronidazole is commonly compounded in veterinary medicine into smaller dose sizes and has flavors added to make it less bitter and more appealing to animals. In the event that your pet is hospitalized, metronidazole comes in an injectable formulation that can be administered intravenously.

How Should I Give Metronidazole to My Pet?

Metronidazole should always be administered to your pet by following the label instructions. If you are unclear on anything, please ask your veterinarian for clarification. Because metronidazole is an antibiotic, your pet must be given the entire dosing regimen to avoid bacterial resistance and reoccurrence.

This medication is given by mouth in tablet, capsule, or liquid form. To avoid gastrointestinal upset and stomach pain, it is recommended to administer metronidazole with food if possible.

Remember that the drug has a very bitter taste, and therefore it works best to hide the intact pills or capsules in food to avoid your dog tasting the medication. Liquid formulations may be flavored or mixed into foods to help disguise the taste. If you are having trouble getting your dog to take this medication, please contact your veterinarian so they can assist you.

Side Effects of Metronidazole

Metronidazole may have side effects, most commonly nausea and vomiting. These side effects are typically mild and self-limiting, but it may be difficult to differentiate whether these signs are a result of the illness or side effect of the medication. However, if you think your dog is having a side effect due to metronidazole administration, please contact your veterinarian. Metronidazole may also cause a temporary decrease in ability to smell, which should be kept in mind especially for working dogs; typically this resolves within 10 days of discontinuing the medication.

In rare cases, metronidazole can cause neurological side effects such as lethargy, trembling, stumbling, loss of control of the limbs, and even seizures. These side effects are most commonly seen with overdoses of the medication, but in some dogs with hypersensitivities, they can occur even at lower doses.

Liver toxicity can also occasionally occur, and your veterinarian may use a reduced dose if your dog has liver issues. If you notice your dog not eating, vomiting, or a yellow color or tint to your dog’s eyes, mucous membranes, or skin, you should contact your veterinarian right away.

Missed Doses and What to Do

Just as with medication for ourselves, if you accidentally miss giving a dose, you should give it as soon as you remember. However, if it is close to the time for the next dose, simply skip the dose you missed and continue with the regular dosing plan. Do not give your pet two doses at once to make up for a missed dose.

Contraindications for Metronidazole Use in Dogs

Your veterinarian is your best resource for information on medications for your pet. Always be sure to inform them of any other medications or supplements that your pet is currently taking. This will enable them to avoid drug interactions for your pet.

Metronidazole should be avoided in dogs with a known hypersensitivity or allergy to the medication. It is also not to be given to dogs that are pregnant or nursing. Metronidazole should be used with caution or possibly at lower doses in dogs that have liver dysfunction or disease.

Precautions for Humans

Though metronidazole is labeled for human use, there are some precautions you should take when the medication is prescribed for your dog. Exposure to metronidazole is not recommended for pregnant humans. You should wear gloves when handling the medication and ensure that you wash your hands after administering it. Crushing the pills into powder or removing the medication from capsules is not recommended, as this may lead to airborne exposure in humans.