# Ronidazole: veterinary dose and monograph

> Ronidazole is a veterinary antiparasitic. Nitroimidazole that is the only reliably effective drug for Tritrichomonas foetus diarrhoea in cats. Indications include tritrichomonas foetus colitis (cats). This monograph lists 1 reference dose for cats, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/ronidazole · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Antiparasitic
- **Also known as:** Ronidazole (compounded)
- **Species with doses:** Cats
- **General dose range:** 30 mg/kg PO q24h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Tritrichomonas foetus colitis (cats)

## Ronidazole dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Cats

*Ronidazole doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Tritrichomonas foetus diarrhoea | 30 mg/kg | PO | q24h | 14 days |

- Tritrichomonas foetus diarrhoea: Papich 5e and Plumb’s p.1050 (Tolbert & Gookin 2009): 30 mg/kg PO once daily for 14 days. Early studies used q12h, but twice-daily dosing is more likely to cause CNS toxicity. Papich 5e: no dog dose reported.

## Contraindications

Neurological disease; pregnancy and lactation. Stop at the first sign of neurotoxicity (ataxia, tremors, seizures). Confirm T. foetus (PCR/culture) before treating.

## Species-specific warnings

> **Caution:** Cats: Neurotoxicity is the main risk — stop immediately if lethargy, ataxia or tremors appear.

## Adverse effects

- Neurotoxicity (lethargy, ataxia, tremors, seizures) — more likely with q12h dosing
- Inappetence

## Formulations and products

- Compounded capsules (from bulk powder)

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Ronidazole for cats?

Reference doses for Ronidazole in cats: 30 mg/kg PO q24h for 14 days (Tritrichomonas foetus diarrhoea). Confirm against the label and the patient before use.

### When should Ronidazole not be used?

Neurological disease; pregnancy and lactation. Stop at the first sign of neurotoxicity (ataxia, tremors, seizures). Confirm T. foetus (PCR/culture) before treating.

### What are the side effects of Ronidazole in animals?

Neurotoxicity (lethargy, ataxia, tremors, seizures) — more likely with q12h dosing; Inappetence.

## Sources

- Plumb's Veterinary Drug Handbook
- Papich 5e — Ronidazole
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.