Florfenicol

Florfenicol is a fluorinated amphenicol antibacterial used extensively in livestock medicine. Established applications include bovine and porcine respiratory disease, with additional species- and product-specific indications in cattle, fish and other animals. It is available in several delivery systems whose clinical coverage depends on the intended host and formulation.

Group

Amphenicol antibacterial

Mechanism of Action

Florfenicol binds the bacterial 50S ribosomal subunit and inhibits peptide-bond formation and protein synthesis. Suppression of essential protein production inhibits growth and can produce bactericidal activity against some susceptible pathogens. Its structure reduces susceptibility to certain chloramphenicol-inactivating enzymes, although efflux and other mechanisms can still confer resistance.

Dose Rates

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Bovine respiratory disease	20 mg/kg	IM	Every 48 h	Two injections total, in the neck. Nuflor 300 mg/mL: maximum 10 mL per site.
Bovine respiratory disease	40 mg/kg	SC	Once	Nuflor: maximum 10 mL/site; Nuflor Gold: maximum 15 mL/site, in the neck.

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Susceptible systemic infection	20 mg/kg	IM	Every 8 h	Up to 5 days; Course 3-5 days; injection may be painful.

Cats

Use / stage	Dose	Route	Schedule	Instructions
Susceptible systemic infection	22 mg/kg	IM, PO	Every 12 h	Up to 5 days; Course 3-5 days. Oral use requires a suitable formulation, not automatic oral administration of any injection.

Pigs

Use / stage	Dose	Route	Schedule	Instructions
Respiratory infection - drinking water	Reference only	PO		Up to 5 days; NuFlor concentrate water regimen: 100 mg/L as the only drinking water for 5 days. The source also approximates this as 400 mg/US gallon; base preparation on the stated metric concentration.

Goats

Use / stage	Dose	Route	Schedule	Instructions
Respiratory disease in kids	Reference only	PO		Source describes 20 mg/kg daily for 2 days but does not establish the route; no parenteral route is inferred.

Chickens

Use / stage	Dose	Route	Schedule	Instructions
Susceptible bacterial infection - drinking water	Reference only	PO		Up to 5 days; Fenlor 100 mg/mL: 1 mL per litre of drinking water for 3-5 days; prepare to actual daily water consumption.

Indications

Treatment of bovine respiratory disease caused by susceptible Mannheimia haemolytica, Pasteurella multocida or Histophilus somni, and other product-supported pathogens.
Treatment of susceptible bovine interdigital necrobacillosis or infectious keratoconjunctivitis where included in the product indication.
Treatment of selected susceptible porcine respiratory infections.
Treatment of selected bacterial infections in aquaculture with an indicated fish product.
Selected poultry or other veterinary bacterial infections where supported by the corresponding product and susceptibility evidence.

Contraindications

Do not administer injectable products IV.
Breeding-animal and lactating-dairy restrictions depend on formulation; cited Nuflor products exclude female dairy cattle 20 months or older and veal calves.

Interactions

Other 50S-binding antibacterials may be antagonistic; clinical significance is uncertain.

Adverse effects

Reduced appetite or water intake, diarrhoea and injection-site lesions.
Rare hypersensitivity or collapse.

Toxicity

Overdose may amplify gastrointestinal effects and liver-enzyme changes; provide supportive care.

Preparations

Preparation	Form	Strength	Route
NuFlor injection 300 mg/mL Protect from inappropriate heat; in-use period 28 days at 2-30°C.	Injection	300 mg / mL	IM, SC
Fenlor oral solution 100 mg/mL Selmore Pharmaceuticals (Pvt) Ltd. Shake; use medicated water within 24 hours. Store at 15-25°C. Poultry meat withdrawal 7 days.	Oral Liquid	100 mg / mL	PO

Monitoring and Administration

Use the neck for cattle injections. Maximum site volume differs between Nuflor and Nuflor Gold.

Monitor clinical response and injection sites; investigate persistent fever or treatment failure.

Nuflor withdrawal: cattle meat 28 days after IM treatment, 38 days after SC; Nuflor Gold 44 days. These periods are product-specific.