Metronidazole (Flagyl®) for Dogs and Cats

A large number of yellow metronidazole pills on a white table.A large number of yellow metronidazole pills on a white table.
A large number of yellow metronidazole pills on a white table.A large number of yellow metronidazole pills on a white table.

Table of Contents:

  1. Brand Names
  2. Uses of Metronidazole for Dogs and Cats
  3. Precautions and Side Effects
  4. Dosing Information of Metronidazole for Dogs and Cats
  5. Drug Library 

Metronidazole is a synthetic antibiotic and antiprotozoal used to treat and prevent bacterial infections and treat certain parasitic infections in dogs and cats. This drug is not approved for use in animals by the Food and Drug Administration, but it is prescribed legally by veterinarians as an extra-label drug.

Brand Names

  • This drug is registered for use in humans only.
  • Human formulations: Flagyl® (Searle), Metric 21® (Fielding), Protostat® (Ortho), Metro® (McGaw). Metronidazole is supplied by numerous drug companies with a variety of trade names and various generic formulations.
  • Veterinary formulations: None

Uses of Metronidazole for Dogs and Cats

Metronidazole is prescribed to treat or control infections caused by susceptible bacteria and parasites it is effective against infections caused by Giardia, Trichomonas and Balantidium coli. The drug is not effective against viruses.

Precautions and Side Effects

While generally safe and effective when prescribed by a veterinarian, metronidazole can cause side effects in some animals. Negative reactions to the drug may include:

  • Liver damage
  • Loss of appetite
  • Neurological disorders
  • Sluggishness
  • Weakness

Prolonged use or overdoses can cause severe neurological reactions. These may exhibit themselves in symptoms including:

  • Ataxia
  • Disorientation
  • Head tilting
  • Nystagmus
  • Rigidity
  • Seizures
  • Tremors

Metronidazole should only be cautiously administered to pregnant pets and never administered to pets with liver disease. Additionally, the drug may react to other medications that your dog or cat is already taking. These include phenobarbital and cimetidine.

Dosing Information of Metronidazole for Dogs and Cats

Remember that you should never administer any medication to your pet without guidance from your veterinarian.

Solid metronidazole is available in the following forms:

  • 250 milligram tablets
  • 500 milligram tables
  • 375 miligram capsules

The drug also comes in the following liquid quantities:

  • 500 milligram vials
  • 5 milligram/milliliter injectable solutions

The typical dose of metronidazole ranges from 5 to 30 milligram per pound (10 to 60 mg per kilogram) one to four times a day in both dogs and cats.The duration of administration depends on the condition being treated, the pet’s response to the medication, and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, completing the entire treatment plan could prevent your pet’s symptoms from returning.

Drug Library

Browse PetPlace.com’s Drug Library for comprehensive guides to hundreds of dog and cat medications.

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