POM-V Prescription Required

Resflor 300/16.5 mg/ml Solution for Injection for Cattle

Active ingredients: Florfenicol, Flunixin

Form

Injection

Species

Cattle

Manufacturer

Intervet International B.V.

VMD MA No.

06376/5002

What it's used for

Treatment of respiratory infections caused by , multocida, Mycoplasma bovis and Histophilus somni associated with pyrexia.

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 + Flunixin

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.

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Prescription required

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

Clinical information

Resflor 300/16.5 mg/ml Solution for Injection for Cattle — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.

Treatment of respiratory infections caused by ,
multocida, Mycoplasma bovis and Histophilus somni associated with pyrexia.

Subcutaneous use.
40 mg/kg florfenicol and 2.2 mg/kg flunixin (2 mL/15 kg body weight) to be administered by
a single injection.
The dose volume given at any one injection site should not exceed 10 mL.
It is recommended to treat animals in the early stages of the disease and to evaluate the
response to treatment 48 hours after injection. The anti-inflammatory component of the
veterinary medicinal product, flunixin, may mask a poor bacteriological response to
florfenicol in the first 24 hours after injection. If clinical signs of respiratory disease persist
or increase, or if relapse occurs, treatment should be changed, using another antibiotic,
and continued until clinical signs have resolved.
The injection should only be given in the neck.
Swab septum before removing each dose. Use a dry sterile needle and syringe.

Amended pages: March 2025
AN: 00446/2024
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 animals suffering from hepatic and renal diseases.
Do not use if there is a risk of gastrointestinal bleeding or in cases where there is evidence
of altered hemostasis.
Do not use in animals suffering from cardiac diseases.
Do not use in cases of hypersensitivity to the active substances or to any of the excipients.

Amended pages: March 2025
AN: 00446/2024

Cattle:
Very common
(>1 animal / 10 animals treated):
Injection site swelling
Very rare
(<1 animal / 10,000 animals
treated, including isolated
reports):
Anaphylactic-type reaction
Amended pages: March 2025
AN: 00446/2024
becomes palpable 2-3 days after subcutaneous injection. The duration of the injection site
swellings ranged from 15-36 days post-injection. Grossly, this is associated with minimal to
mild irritation of the subcutis. Extension into the underlying muscle was noted in only a few
instances. By 56 days post-dosing, no gross lesions were observed that would require any
trim-out at slaughter.
these reactions may be fatal.
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 the package leaflet for
respective contact details.

None.

Special precautions for use in animals:
Use of the product should be based on susceptibility testing of the bacteria isolated from
the animal. If this is not possible, therapy should be based on local (regional, farm level)
epidemiological information about susceptibility of the target bacteria.
Official and local antimicrobial policies should be taken into account when the product is
used.
Use of the product deviating from the instructions given in the SPC may increase the
prevalence of bacteria resistant to florfenicol.
Avoid use in dehydrated, hypovolaemic or hypotensive animals as there is a potential risk
of increased renal toxicity. Concurrent administration of potentially nephrotoxic drugs
should be avoided.
Repeated daily dosing has been associated with abomasal erosions in the pre-ruminant
calf. The product should be used with caution in this age group.
The safety of the product has not been tested in calves of 3 weeks of age or less.
Flunixin is toxic to avian scavengers. Do not administer to animals susceptible to enter wild
fauna food chain. In case of death or sacrifice of treated animals, ensure that they are not
made available to wild fauna.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
Care should be taken to avoid accidental self-injection.
People with known hypersensitivity to propylene glycol and polyethylene glycols should
avoid contact with the veterinary medicinal product.
Wash hands after use.
Laboratory studies in rabbits and rats with the excipient N-methyl pyrrolidone have shown
evidence of foetotoxic effects. Women of childbearing age, pregnant women or women
suspected of being pregnant should use the veterinary medicinal product with serious
caution to avoid accidental self-injection.
Special precautions for the protection of the environment:
Not applicable.

Concurrent use of other active substances that have a high degree of protein binding may
compete with flunixin for binding and thus lead to toxic effects. Pre-treatment with other
anti-inflammatory substances may result in additional or increased adverse effects and
accordingly a treatment-free period with such drugs should be observed for at least 24
hours before the commencement of treatment. The treatment-free period, however, should
take into account the pharmacokinetic properties of the products used previously.
The product must not be administered in conjunction with other NSAIDs or
glucocorticosteroids. Gastrointestinal tract ulceration may be exacerbated by
corticosteroids in animals given NSAIDs.

Do not store above 25°C.
Do not freeze. Protect from frost.

Meat and offal: 46 days.
Milk: Not authorised for use in animals producing milk for human consumption. Do not use
in pregnant animals which are intended to produce milk for human consumption within 2
months of expected parturition.
5.

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.