# Norfloxacin: veterinary dose and monograph

> Norfloxacin is a veterinary antibiotic. Older second-generation fluoroquinolone with predominantly Gram-negative activity that concentrates in the urinary tract and gut — historically used for UTIs and enteric infections, and very common and inexpensive in India (Norflox)… Indications include lower urinary tract infection (Gram-negative); bacterial enteritis / colibacillosis; poultry colibacillosis (water medication, where legally permitted). This monograph lists 2 reference doses for dogs and cats, each with route, frequency and source.

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

## At a glance

- **Drug class:** Antibiotic
- **Also known as:** Norflox, Noroxin, Norbactin
- **Species with doses:** Dogs and Cats
- **General dose range:** 5–11 mg/kg PO q12–24h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Lower urinary tract infection (Gram-negative)
- Bacterial enteritis / colibacillosis
- Poultry colibacillosis (water medication, where legally permitted)
- Susceptible Gram-negative soft-tissue infection (limited tissue penetration)

## Norfloxacin 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.

### Dogs

*Norfloxacin doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| UTI / enteric infection | 22 mg/kg | PO | q12h | — |

- UTI / enteric infection: Papich 5e: dogs and cats 22 mg/kg q12h PO. Not in Plumb’s. Mainly urinary concentrations; avoid in growing dogs. (The previous 5–11 mg/kg was below the reference.)

### Cats

*Norfloxacin doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| UTI (susceptible organisms) | 22 mg/kg | PO | q12h | — |

- UTI (susceptible organisms): Papich 5e: dogs and cats 22 mg/kg q12h PO.

### Cattle

*Norfloxacin doses for cattle*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Not recommended (food-animal fluoroquinolone) | No reference dose; extra-label fluoroquinolone use in food animals is prohibited in the US and restricted elsewhere | — | — | — | Withdrawal NOT established — treat as extra-label |

- Not recommended (food-animal fluoroquinolone): Papich 5e: no large-animal doses reported; not in Plumb’s.

### Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

*Norfloxacin doses for buffalo*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Not recommended (food-animal fluoroquinolone) | No reference dose; extra-label fluoroquinolone use in food animals is prohibited in the US and restricted elsewhere | — | — | — | Withdrawal NOT established — treat as extra-label |

- Not recommended (food-animal fluoroquinolone): Papich 5e: no large-animal doses reported; not in Plumb’s.

### Birds

*Norfloxacin doses for birds*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Not recommended (food-animal fluoroquinolone) | No reference dose; fluoroquinolone use in poultry is banned or restricted in many countries | — | — | — |

- Not recommended (food-animal fluoroquinolone): Papich 5e reports no large-animal or avian doses; not in Plumb’s. Verify local law before any use in food-producing birds.

## Contraindications

Growing animals (arthropathy). Fluoroquinolone restrictions in food animals (verify legality — poultry fluoroquinolone use is banned/limited in many countries). Seizure disorders. Known hypersensitivity. Pregnancy where alternatives exist.

## Species-specific warnings

> **Caution:** Birds: Fluoroquinolone use in poultry is banned/restricted in many countries (resistance concerns) — verify legality before flock use.

## Adverse effects

- GI upset
- Cartilage damage in growing animals
- CNS excitation/seizures (rare)
- Crystalluria in alkaline urine

## Drug interactions

- Di-/tri-valent cations (antacids, sucralfate, dairy, iron/calcium/zinc): chelation reduces absorption — separate by ≥2 h
- Theophylline: reduced clearance → toxicity
- NSAIDs: additive CNS excitation
- Warfarin: potentiated anticoagulation

## Pregnancy and lactation

Avoid in pregnancy where alternatives exist (fetal arthropathy risk).

## Monitoring

- Urine culture (confirm cure for UTI)
- Renal function on prolonged use
- CNS signs in at-risk patients
- Legal compliance for any food-animal use

## Toxicity and overdose

Overdose: GI upset, CNS excitation/seizures, crystalluria. Cartilage toxicity in juveniles (class effect). Generally less potent/penetrating than newer fluoroquinolones.

Management: No specific antidote. Decontaminate if recent ingestion; IV fluids to maintain urine flow and prevent crystalluria; control seizures with benzodiazepines. Supportive care.

## Clinical pearls

- A cheap, widely available urinary/enteric fluoroquinolone — but its poor tissue penetration limits it to lower UTI and gut infections
- For systemic or deep infections, choose a newer fluoroquinolone (enrofloxacin, marbofloxacin, pradofloxacin)
- Separate from antacids/sucralfate/dairy by ≥2 h
- Be aware that poultry/food-animal fluoroquinolone use is restricted or banned in many jurisdictions

## Mechanism of action

Inhibits bacterial DNA gyrase (and topoisomerase IV), blocking DNA supercoiling/replication — concentration-dependent bactericidal action. Its pharmacokinetics favour urinary and gut concentrations over systemic tissue levels, which defines its clinical niche.

## Formulations and products

- 400 mg tablet
- Oral/water-soluble powder (poultry)
- Norflox — 400 mg tablet, Tablet (human-label)
- Norbactin — 400 mg tablet, Tablet (human-label)

## Storage

Tablets/powder: 15–30 °C, protect from light and moisture. Medicated water: prepare fresh daily.

## 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.

## Other antibiotics

- [Minocycline](https://vetmasterji.com/drugs/minocycline)
- [Mupirocin](https://vetmasterji.com/drugs/mupirocin)
- [Neomycin](https://vetmasterji.com/drugs/neomycin)
- [Nitrofurantoin](https://vetmasterji.com/drugs/nitrofurantoin)
- [Orbifloxacin](https://vetmasterji.com/drugs/orbifloxacin)
- [Ornidazole](https://vetmasterji.com/drugs/ornidazole)
- [Oxytetracycline](https://vetmasterji.com/drugs/oxytetracycline)
- [Penicillin G](https://vetmasterji.com/drugs/penicillin-g)

## Frequently asked questions

### What is the dose of Norfloxacin for dogs?

Reference doses for Norfloxacin in dogs: 22 mg/kg PO q12h (UTI / enteric infection). Confirm against the label and the patient before use.

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

Reference doses for Norfloxacin in cats: 22 mg/kg PO q12h (UTI (susceptible organisms)). Confirm against the label and the patient before use.

### Can Norfloxacin be given to cattle?

No reference dose; extra-label fluoroquinolone use in food animals is prohibited in the US and restricted elsewhere (Not recommended (food-animal fluoroquinolone)).

### When should Norfloxacin not be used?

Growing animals (arthropathy). Fluoroquinolone restrictions in food animals (verify legality — poultry fluoroquinolone use is banned/limited in many countries). Seizure disorders. Known hypersensitivity. Pregnancy where alternatives exist.

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

GI upset; Cartilage damage in growing animals; CNS excitation/seizures (rare); Crystalluria in alkaline urine.

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- 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.