MDose · Veterinary drug reference
METRONIDAZOLE
Favorites and recent references stay on this device. No patient data is stored.
Choose the species
One selection filters the source overview, clinical facts, reports and dose calculator. Literature references are not species-filtered.
Choose one species for its overview and dose calculator, or all species to browse the full evidence.
Source overview
Recorded excerpts for one species. Each dose remains a separate source entry; no regimen is selected.
Choose one species to view its source overview. All-species evidence remains available below.
View full clinical evidence and sources ↓Clinical evidence
Pending clinical review (PROPOSED)Rule-based (RULE_BASED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Giardia, other enteric protozoa, anaerobic infections, adjunct for IBD/colitis
DogCatExtra-label (EXTRA_LABEL)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Giardia, other enteric protozoa, anaerobic infections, adjunct for IBD/colitis — Extra-label (no vet FDA-approved product)
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Giardia, other enteric protozoa, anaerobic infections, adjunct for IBD/colitis — Extra-label (no vet FDA-approved product)
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens7
This calculator performs arithmetic only on the sourced dosing field shown for each result — it does not verify the field's accuracy, does not select which field to use for a patient, and does not replace a veterinarian's order. Not for clinical use. Confirm every result against the primary source before dispensing.
Choose one species above to view its dose calculator.
Adverse effects203
Neurotoxicity (ataxia, nystagmus, head tilt, seizures) — Dose-related, typically >60 mg/kg/day or chronic "recommended" dosing
DogNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Hepatotoxicity, vomiting, anorexia — Reported
CatNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Peripheral neuropathy, hepatopathy, ↓ appetite — Higher-dose related
HorseNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Horse · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
These are counts of spontaneously reported events, not proven adverse effects, causal relationships, or incidence rates.
Bars compare report counts within each species; they do not show incidence.
More reportsFewer reportsDog
- Diarrhoea859 reports
- Vomiting835 reports
- Lethargy (see also Central nervous system depression in 'Neurological')502 reports
- Anorexia374 reports
- Other abnormal test result NOS364 reports
- Death by euthanasia341 reports
- Elevated alanine aminotransferase (ALT)339 reports
- Bloody diarrhoea278 reports
- Not eating273 reports
- Weight loss254 reports
- Elevated serum alkaline phosphatase (SAP)248 reports
- Death235 reports
Cat
- Diarrhoea121 reports
- Vomiting65 reports
- Weight loss61 reports
- Lethargy (see also Central nervous system depression in 'Neurological')60 reports
- Death by euthanasia39 reports
- Not eating37 reports
- Anorexia30 reports
- Other abnormal test result NOS28 reports
- Ataxia26 reports
- Behavioural disorder NOS26 reports
- Dehydration26 reports
- Death25 reports
Monitoring1
Neurologic status, especially with chronic/high-dose therapy
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
Hypersensitivity to nitroimidazoles; food-producing animals (FDA prohibited)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions4
Severe debilitation, pregnancy, hepatic dysfunction (reduce to 25–50% usual dose)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Total daily dose should not exceed 65 mg/kg/day (dogs) — the classic "metronidazole toxicity" vestibular/cerebellar syndrome is dose-related and usually reversible within 1–2 days of discontinuation; diazepam can hasten recovery.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Sharp metallic taste — very unpalatable, especially when tablets are crushed in cats; metronidazole benzoate (compounded, not commercially available in US) has a blander taste.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Never give the injectable form undiluted/unbuffered IV — highly acidic.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions4
Alcohol — Disulfiram-like reaction
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Cimetidine — ↓ metronidazole metabolism, ↑ side-effect risk
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Phenobarbital/phenytoin — ↑ metronidazole metabolism, ↓ levels
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Warfarin/cyclosporine — Metronidazole potentiates both via metabolic inhibition
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics5
Bioavailability — 50–100% (dog), highly variable
CatNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Protein binding — <20% (human data)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Half-life — 4–5h (dog); ~5–6h (cat, slightly longer, not statistically significant)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Metabolism — Extensive hepatic
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Elimination — Urine + feces
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
Controversial teratogenicity data; avoid especially in first 3 weeks of gestation. Papich canine/feline class C. Consider milk replacer for nursing patients (tumorigenicity concern).
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 825–828; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 524–526 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references15
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- Antibacterial and antivirulence activities of abafungin against Clostridioides difficile: in vitro and in vivo studies.
Study summary not available in the imported record. Open the original citation to review the study.
- Widespread use of nitroimidazoles in competition pigeons reduced their effectiveness against Trichomonas gallinae.
Study summary not available in the imported record. Open the original citation to review the study.
- A brief review on herbal extracts and essential oils for the control of Demodex spp. mites.
Study summary not available in the imported record. Open the original citation to review the study.
- Omeprazole as a Novel Treatment Option for Giardiasis in Cats.
Study summary not available in the imported record. Open the original citation to review the study.
- Gut microbiota bidirectionally influences protection and severity in cerebral malaria in mice.
Study summary not available in the imported record. Open the original citation to review the study.
Sources: PubMed, National Library of Medicine; openFDA, U.S. Food and Drug Administration; Plumb DC. Plumb's Veterinary Drug Handbook. 7th ed. PharmaVet Inc; 2011.
Owner information handout
Plain-language medication information to review with the owner. Open the handout to print it or download a PDF.
Available products
Products listed in the Health Canada Drug Product Database for this active ingredient. A listing does not establish that a product is authorized for the clinical uses described on this page.