Metronidazole
Also known as: Flagyl, Metrobactin, Stomorgyl
**Important Guidance for Pet Owners:** * **Extremely Bitter Taste:** Metronidazole tablets taste terrible to animals. Do not crush the tablets unless absolutely necessary, as the bitter taste will cause your pet (especially cats) to drool excessively or refuse food. If you are struggling to give the medication, ask your veterinarian about a compounded liquid version (metronidazole benzoate) which hides the taste much better. * **Give with Food:** Giving this medication with a meal can help improve its absorption and reduce stomach upset. * **Watch for Neurologic Signs:** Contact your veterinarian immediately if your pet shows any signs of neurologic toxicity. Look for: stumbling or "drunken" walking (ataxia), rapid back-and-forth eye movements (nystagmus), head tilt, extreme lethargy, tremors, or seizures. * **Complete the Course:** Even if your pet's diarrhea or symptoms improve, finish the entire prescription to ensure the infection or parasite is fully cleared.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Giardia
- Giardia
- Giardia
- Entamoeba histolytica or Pentatrichomas hominis
- H. pylori
- Sepsis
- Inflammatory bowel disease (mild to moderate large bowel)
- Inflammatory bowel disease
- Inflammatory bowel disease (moderate to severe)
- Hepatic encephalopathy
- Helicobacter mustelae gastritis infections
- Helicobacter mustelae gastritis infections
- Susceptible infections
- Inflammatory bowel disease
How it is given
Possible side effects
- Neurologic disorders (ataxia, nystagmus, seizures, head-tilt)
- Lethargy and weakness
- Neutropenia
- Hepatotoxicity
- Hematuria
- Anorexia, nausea, vomiting, and diarrhea
- Hypersalivation (especially in cats due to bitter taste)
- Vomiting
- CNS toxicity (nystagmus, ataxia, knuckling, head tilt, seizures)
- Haematuria
- Excessive salivation/foaming (especially in cats)
- Impaired sense of smell (reported in explosive detection dogs)
Cautions & contraindications
- Hypersensitivity to metronidazole or other nitroimidazole derivatives
- Food-producing animals (FDA prohibited)
- Pregnancy (potential teratogen, especially in early pregnancy)
- Severe hepatic disease (requires dose reduction)
- > **Neurotoxicity Warning:** In dogs, total daily doses should not exceed 65 mg/kg/day to minimize the risk of central vestibular and cerebellar toxicity. Toxicity can occur with acute high doses or chronic moderate-to-high dose therapy. * **Hepatic Impairment:** Use with caution in animals with hepatic dysfunction. Consider reducing the dose to 25-50% of the usual dose in significant liver impairment. * **Pregnancy:** Potential teratogen. Avoid use during pregnancy, particularly during the first 3 weeks of gestation, unless benefits clearly outweigh risks. * **Nursing:** Consider alternative therapy or switching to milk replacer due to potential tumorigenicity. * **Debilitated Patients:** Use with extreme caution in severely debilitated animals.
Drug interactions
- Alcohol: May induce a disulfiram-like reaction (nausea, vomiting, cramps).
- Cimetidine: May decrease the metabolism of metronidazole, increasing the likelihood of dose-related side effects.
- Phenobarbital: May increase the metabolism of metronidazole, thereby decreasing blood levels.
- Phenytoin: May increase the metabolism of metronidazole, thereby decreasing blood levels.
- Warfarin: May prolong the prothrombin time (PT). Avoid concurrent use or intensify monitoring.
- Macrolide antibiotics: Should not be used concurrently with Spiramycin (in combination products) as the combination may be antagonistic.
Frequently asked questions
What is Metronidazole used for in pets?
**Important Guidance for Pet Owners:** * **Extremely Bitter Taste:** Metronidazole tablets taste terrible to animals. Do not crush the tablets unless absolutely necessary, as the bitter taste will cause your pet (especially cats) to drool excessively or refuse food. If you are struggling to give the medication, ask your veterinarian about a compounded liquid version (metronidazole benzoate) which hides the taste much better. * **Give with Food:** Giving this medication with a meal can help improve its absorption and reduce stomach upset. * **Watch for Neurologic Signs:** Contact your veterinarian immediately if your pet shows any signs of neurologic toxicity. Look for: stumbling or "drunken" walking (ataxia), rapid back-and-forth eye movements (nystagmus), head tilt, extreme lethargy, tremors, or seizures. * **Complete the Course:** Even if your pet's diarrhea or symptoms improve, finish the entire prescription to ensure the infection or parasite is fully cleared.
Is Metronidazole safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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