Dog owners today are armed with more tools for keeping their dogs healthy and fit than ever before. Modern medicine has radically improved how well, and how long, our companion animals live. For both humans and dogs, antibiotics continue to be a potent ally in the fight against disease and infection.
What Is Metronidazole?
Metronidazole (also known by the brand names Flagyl, Metizol, Protostat, Metrogel) is a strong antibiotic primarily used as an antidiarrheal to treat inflammation of the large intestine. It’s also used for other illnesses and conditions in dogs, cats, and horses, as well as to treat bacterial infections in humans. It is often prescribed in combination with other antibiotics.
Metronidazole is a prescription-only medication that can be taken orally or used topically, depending on the illness being treated. The U.S. Food and Drug Administration has not yet approved metronidazole for veterinary use (it is approved for human use), but veterinarians often prescribe it for their canine and feline patients. Many of the parasites and bacteria that make us sick also affect our pets, and this is one human medication that can often help them.
What Is Metronidazole Used For?
Metronidazole treats bacterial infections and some parasites, so it is prescribed to treat a variety of conditions and to relieve their symptoms. It’s often used to treat:
- Giardia (and other parasites)
- Inflammatory Bowel Disease (IBD)
- Oral and dental infections
- Other bacterial infections that cause diarrhea or sepsis, abscesses, meningitis
How Does It Work?
Metronidazole works by destroying and preventing the creation of DNA in the infecting organisms. Unlike most other drugs, metronidazole is able to treat central nervous system infections by penetrating the blood-brain barrier.
In order to thrive, your dog’s body parts need good circulation and oxygen. Tissue that is damaged usually has poor oxygen circulation. In these areas, only certain pathogens that do not require oxygen can thrive. Metronidazole inhibits repair enzymes in the cells that exist in these unoxygenated (anaerobic) environments, resulting in the death of bacterial cells.
Guidelines for Safe Use
Metronidazole is considered very safe. However, it should not be prescribed to pregnant bitches or young puppies, and should be considered carefully before being prescribed to dogs that are nursing. It may also not be suitable for pets with kidney disease, liver disease, neutropenia (low white blood cell count), or seizure disorders.
Before using any medication for your pet, it’s best to speak to your veterinarian. You should:
- Discuss any other medicine your dog is taking and the dog’s medical conditions.
- Be cautious when using the drug for extended periods of time, since adverse effects are more common during long-term use.
- If you are giving your dog metronidazole to remedy diarrhea, be sure to provide lots of fresh water to prevent the dog from becoming dehydrated.
Does Metronidazole Have Side Effects?
Though it’s rare, some dogs may suffer from neurotoxic (nervous system) side effects, such as paralysis in all four legs, or they may have an allergic reaction — hives, rash, rapid heartbeat, or difficulty breathing. If this happens, contact a veterinarian right away because an allergic reaction can become dangerous quickly or may even be life-threatening.
Some more common side effects your dog may experience include:
- Loss of appetite
- Discoloration of urine
Dogs who receive too much of this medicine, or those treated with metronidazole for extended periods of time, will need emergency veterinary attention if they experience:
- Irregular or abnormally slow heartbeat
- Stiffness or muscle spasms
- Dilated pupils or eye twitching
Intestinal inflammation, parasites, bacterial infections and their accompanying symptoms, such as diarrhea, are serious adversaries for our dogs. Thankfully, we are able to utilize powerful medical weapons such as metronidazole to help them recover.
This article is designed to help inform you about metronidazole in dogs and is not meant to take the place of veterinary advice and consultation.
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