General Drug Information and Indications

Antibiotic/antiprotozoal for anaerobic infections, giardiasis, IBD, and hepatic encephalopathy in horses, dogs, and cats. Nitroimidazole antibiotic/antiprotozoal. Mechanism: reductive activation to nitro-radical intermediates by anaerobic organisms' electron transport proteins → DNA double-strand breaks → cell death. Selective for strict anaerobes and microaerophilic organisms (Giardia, Tritrichomonas, Clostridium, Bacteroides). Good CNS penetration. Oral or IV administration. Key information Do NOT exceed recommended dose — neurotoxicity (vestibular signs, ataxia) especially at high doses or prolonged use. Do not use in first trimester pregnancy. Avoid alcohol-based products concurrently (in humans — Antabuse-like reaction). IV: infuse slowly over 30–60 min.

How to Give this Medication

Oral: Administer orally. May be given with food to improve compliance and reduce GI upset. Administer with food to reduce GI adverse effects. May crush tablets for compliance. IV: infuse over 30–60 min. Store at room temperature; protect from light. If a dose is missed Administer as soon as you remember. If it is almost time for the next scheduled dose, skip the missed dose and resume the normal schedule. Never double up doses to make up for a missed one.

Side Effects

GI: nausea, vomiting, anorexia (common). Neurological (overdose/prolonged use): vestibular signs, ataxia, seizures (discontinue immediately if neurological signs develop — usually reversible with diazepam). Hepatotoxicity. Potential teratogen.

Precautions

For animals Avoid in CNS disease. Use with caution in hepatic impairment. Monitor for neurotoxicity. Avoid in pregnant animals. in first two-thirds of pregnancy. Drug interactions: warfarin (increased anticoagulant effect), barbiturates. For people handling this medication Wear gloves when handling. Wash hands thoroughly with soap and water after handling. Potential carcinogen with prolonged handling. Wear gloves. Keep out of reach of children. Pregnant women and women of childbearing age should avoid contact. Avoid during first trimester.

Overdose

Contact your veterinarian immediately. Overdose causes serious neurological signs including vomiting, disorientation, circling, seizures, and balance loss. Do not give additional doses. Supportive care required. Contact your veterinarian, a veterinary emergency clinic, or the ASPCA Animal Poison Control Center (888-426-4435) immediately. Do not induce vomiting unless specifically directed by a veterinary professional.

Metronidazole Tab dosage forms

ProductStrengthFormSizeType
METRONIDAZOLE INJ 500MG/100ML BAG500MGInjectable—Commercial
METRONIDAZOLE INJ 500MG/100ML BAG500MGInjectable—Commercial
METRONIDAZOLE INJ 500MG/100ML BAG500 MGInjectable1Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial
METRONIDAZOLE TAB 500MG500MGTablet—Commercial

Sources

This information is provided for educational purposes and is not a substitute for advice from your veterinarian. Source: Merck Veterinary Manual (merckvetmanual.com); Plumb's Veterinary Drug Handbook (Plumb, D.C., app.plumbs.com)