Metronidazole Use in Dogs

Metronidazole is a common medication, used by both doctors and veterinarians to treat a number of ailments including intestinal inflammation, giardia infections and other diarrheal diseases. Because of the medication’s unique properties, it can alleviate many disorders that are difficult to treat in other ways. Although it is considered safe, you must observe your dog closely during metronidazole treatments, and report any troubling symptoms to your vet.

Vet holding a dog paw
A dog with the vet.
credit: andresrimaging/iStock/Getty Images

Anti-bacterial Basics

Metronidazole is sold under a number of brand names, including Flagyl, Metizol, Protostat and Metrogel. A fat soluble drug, metronidazole is available in liquid, tablet and injectable forms. Your vet will prescribe the form most applicable to your dog’s illness. Metronidazole is a controlled substance, requiring a veterinary prescription to purchase it.

Fantastically Functional

While the drug has a number of potential applications, metronidazole is highly effective for treating many different protozoans and bacteria -- particularly anaerobic bacteria, which are common in areas devoid of oxygen. The precise mechanism by which metronidazole works is not clear, but it is likely that the drug bonds with the DNA of bacterial and protozoal cells, thereby disrupting the molecule’s function. Veterinarians also prescribe metronidazole to treat infections of the bones or teeth. Additionally, because the medication is able to cross the blood-brain barrier, it is helpful for treating infections of the central nervous system.

Doggie Dosage

Your veterinarian will weigh your dog and calculate the correct dosage, as different ailments require different dosages. Most often, metronidazole treatment lasts five to seven days -- always be sure to complete the full course of the medication, even if your dog’s symptoms improve. Veterinarians often instruct owners to administer oral tablets at meal times to improve absorption. The tablets have a bitter taste, which sometimes makes dogs reluctant to swallow the medication.

Catch-All Cocktails

Sometimes, infections can precipitate from several different bacteria. To treat such infections -- and guard against antibiotic resistance -- veterinarians and doctors often prescribe metronidazole as part of a multiple medication “cocktail.” For example, metronidazole may help eradicate bacteria living in the bones or abscesses, while another antibiotic treats pathogenic aerobic bacteria in other parts of the body.

Contraindicated Conditions

Do not administer the drug to lactating females or young puppies. Inform your veterinarian of any other medications your dog is taking, especially sedatives, anticoagulants, cimetidine, phenytoin or phenobarbital, as these substances may interact dangerously with metronidazole or render it less effective. Additionally, be sure your veterinarian is aware of any kidney or liver problems your dog suffers from, which can reduce your pet’s ability to filter the drugs from his system properly. Immediately consult your veterinarian if your dog displays signs of lethargy, imbalance, weakness, anorexia or vomiting while taking metronidazole, as these symptoms may indicate problems with your pet’s central nervous system.