Metronidazole

What is this medication for?

• Giardia, other enteric protozoa, anaerobic infections, adjunct for IBD/colitis

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Sharp metallic taste — very unpalatable, especially when tablets are crushed in cats; metronidazole benzoate (compounded, not commercially available in US) has a blander taste.
• Never give the injectable form undiluted/unbuffered into a vein — highly acidic.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• None commonly reported; call your clinic with any concern.

Worth a phone call to your veterinarian

• Hepatotoxicity, vomiting, loss of appetite (Reported)
• Peripheral neuropathy, hepatopathy, ↓ appetite (Higher-dose related)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Neurotoxicity (wobbliness/unsteadiness, nystagmus, head tilt, seizures) (Dose-related, typically >60 mg/kg/day or chronic "recommended" dosing)

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Hypersensitivity to nitroimidazoles; food-producing animals (FDA prohibited)
• has or has had: Severe debilitation, pregnancy, hepatic dysfunction (reduce to 25–50% usual dose)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Alcohol
  • Cimetidine
  • Phenobarbital/phenytoin
  • Warfarin/cyclosporine

Storage and handling

Room temperature. Compounded suspensions: ~28 days stability in some vehicles, up to 90 days in Ora-Plus/Ora-Sweet. into a vein solution must be neutralized with sodium bicarbonate before infusion (too acidic as-is).

Good to know

• 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.
• Sharp metallic taste — very unpalatable, especially when tablets are crushed in cats; metronidazole benzoate (compounded, not commercially available in US) has a blander taste.
• Never give the injectable form undiluted/unbuffered into a vein — highly acidic.