POM-V Prescription Required

Fenflor 300 mg/ml Solution for Injection for Cattle

Active ingredient: Florfenicol

Form

Injection

Species

Cattle

Manufacturer

KRKA, d.d., Novo mesto

VMD MA No.

01656/5116

What it's used for

Treatment and metaphylaxis of respiratory tract infections in cattle due to Mannheimia haemolytica, Pasteurella multocida and Histophilus somni presence of...

Full indications, dosage and side effects ↓

View official SPC (PDF)

The prescription itself has a price. See what practices near you charge for a consultation and the written prescription fee.

Paying less for Florfenicol

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

Fill it at a registered online retailer

The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

Your prescription rights → VMD register of retailers →

Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Fenflor 300 mg/ml Solution for Injection for Cattle — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 27 Mar 2026.

Treatment and metaphylaxis of respiratory tract infections in cattle due to
Mannheimia haemolytica, Pasteurella multocida and Histophilus somni
presence of the disease in the herd has been established.

For treatment:
Intramuscular use: 20 mg/kg bodyweight (1 ml/15 kg) to be administered twice 48
hours apart.
Subcutaneous use: 40 mg/kg bodyweight (2 ml/15 kg) to be administered once only
using a 16 gauge needle.
For metaphylaxis where the presence of the disease in the herd has been
established:
Subcutaneous use: 40 mg/kg bodyweight (2 ml/15 kg) to be administered once only
using a 16 gauge needle.
The dose volume given at any one injection site should not exceed 10 ml.
The injection should only be given in the neck.
To ensure a correct dosage, body weight should be determined as accurately as
possible.

Do not use in adult bulls intended for breeding purposes.
Do not use in cases of hypersensitivity to the active substance or to any of the
excipients.
Do not use in case of resistance to the active substance.

Cattle:
Very rare
(<1 animal / 10,000 animals
treated, including isolated
reports):
Anaphylactic reactionUndetermined frequency
(cannot be estimated from the
available data)
Reduced food intake
Loose stool
Injection site swelling
Injection site inflammation
1
Quick and complete recovery upon termination of treatment.
After intramuscular administration: may persist for 14 days; after subcutaneous
administration: may persist for 41 days.
After intramuscular administration: may persist for 32 days; after subcutaneous
administration: may persist for 41 days.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or its local representative or the national
competent authority via the national reporting system. See also section 16 of the
package leaflet for contact details.
AN: 03941/2023 & 03943/2023

None.
AN: 03941/2023 & 03943/2023

Special precautions for safe use in the target species:
Swab septum before removing each dose. Use a dry, sterile syringe and needle.
The veterinary medicinal product should be used in conjunction with susceptibility
testing and take into account official and local antimicrobial policies.
Use of the veterinary medicinal product deviating from the instructions given in the
SPC may increase the prevalence of bacteria resistant to florfenicol and may
decrease the effectiveness of treatment with other amfenicols, due to the potential for
cross resistance.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals
Care should be taken to avoid accidental self-injection.
In case of accidental self-injection, seek medical advice immediately and show the
package leaflet or the label to the physician.
Do not use the veterinary medicinal product in known cases of sensitivity to
propylene glycol.
Special precautions for the protection of the environment:
The use of this veterinary medicinal product may pose a risk for terrestrial plants,
cyanobacteria and groundwater organisms.

None known.

This veterinary medicinal product does not require any special storage conditions.

Meat and offal: by i.m. (at 20 mg/kg bodyweight, twice): 30 days
by s.c (at 40 mg/kg bodyweight, once): 44 days
Not authorised for use in animals producing milk for human consumption.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.