POM-V Prescription Required

Primopen 300 mg/ml Suspension for Injection for Cattle, Pigs and Horses

Active ingredient: Procaine Benzylpenicillin

Form

Injection

Species

Cattle Horses Pigs

Manufacturer

Fatro S.p.A.

VMD MA No.

11557/3007

What it's used for

Indicated in the treatment of acute and subacute bovine mastitis in milking cows, accompanied by pain and inflammation caused by bacterial infection sensit...

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 Procaine Benzylpenicillin

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

Primopen 300 mg/ml Suspension for Injection for Cattle, Pigs and Horses — SPC Details

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

Indicated in the treatment of acute and subacute bovine mastitis in milking
cows, accompanied by pain and inflammation caused by bacterial infection
sensitive to penicillin, streptomycin and neomycin therapy.

Administer by deep intramuscular injection once daily. The treatment duration is 3 to 7 days.
The appropriate treatment duration should be chosen based on the clinical needs and
individual recovery of the treated animal. Consideration should be given to the accessibility
of the target tissue and characteristics of the target pathogen.
The recommended daily dose is 12 mg of benzylpenicillin procaine/kg body weight
equivalent to 1 ml/25 kg body weight/day.
The maximum volume to be administered per injection site is 15.5 ml in cattle and 3.2 ml in
pigs.
To ensure a correct dosage, body weight should be determined as accurately as possible.
Clean the area of the injection site and swab with spirit.
Do not use the same injection site more than once during a course of treatment.
Shake well before use.
The bottle may be broached up to 20 times.

Do not use in rabbits, guinea pigs, hamsters or gerbils.
Do not use intravenously.

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AN: 03677/2023 & 03678/2023Page 2 of 8
Do not use in cases of hypersensitivity to the active substance, cephalosporins, procaine or
to any of the excipients.

Cattle:
Very rare
(<1 animal / 10,000 animals treated, including
isolated reports):
Allergic reaction
Horses:
Very rare
(<1 animal / 10,000 animals treated, including
isolated reports):
Allergic reaction

Death
Undetermined frequency
(cannot be estimated from the available data):
Locomotor
disturbance
Behavioural disorder
: Potentially
Pigs:
Very rare
(<1 animal / 10,000 animals treated, including
isolated reports):
Allergic reactionUndetermined frequency
(cannot be estimated from the available data):
Vaginal discharge
Pyrexia
, Listless
Vomiting
Incoordination
, Shivering
1
: In pregnant sows and gilts could be associated with abortion.
: Transient.
Systemic toxic effects have been observed in young piglets, which are transient but can be
potentially lethal, especially at higher doses.
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.

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AN: 03677/2023 & 03678/2023Page 4 of 8

The product will not be effective against beta lactamase producing organisms.
After absorption, benzylpenicillin poorly penetrates biological membranes (e.g., blood-brain
barrier) since it is ionised and poorly lipid soluble. Use of the product for treatment of
meningitis or CNS infections due to e.g.,
not be efficacious. Furthermore, benzylpenicillin penetrates mammalian cells poorly and
hence this product may have little effect in treating intracellular pathogens e.g.,
monocytogenes
Elevated MIC values or bi-modal distribution profiles suggesting acquired resistance have
been reported for the following bacteria:
- spp. causing MMA/PPDS, spp. and
S. suis in pigs;
- causing metritis and
member states), as well as spp.,
lignieresii and Trueperella pyogenes in cattle.
Use of the veterinary medicinal product may result in a lack of clinical efficacy when treating
infections caused by these bacteria.

Special precautions for safe use in the target species:
Use of the product should be based on identification and susceptibility testing of the target
pathogens. If this is not possible, therapy should be based on epidemiological information
and knowledge of susceptibility of the target pathogens at farm level, or at local/regional
level.
Use of the product should be in accordance with official, national and regional antimicrobial
policies.
Use of the product deviating from the instructions given in the SPC may increase the
prevalence of bacteria resistant to benzylpenicillin and may decrease the effectiveness of
treatment with other penicillins and cephalosporins due to the potential for cross-resistance.
Special precautions to be taken by the person administering the veterinary medicinal product
to animals
Penicillins and cephalosporins may cause hypersensivity (allergy) following injection,
inhalation, ingestion or skin contact.
Hypersensitivity to penicillin may lead to cross reactions to cephalosporins and vice versa.
Allergic reactions to these substances are occasionally serious.
Handle this product with great care to avoid exposure, taking all recommended precautions.
People with known hypersensitivity to penicillin should avoid contact with the veterinary
medicinal product. If you develop symptoms following exposure, such as skin rash, you
should seek medical advice and show the doctor this warning. Swelling of the face, lips or

Amended pages: March 2025
AN: 03677/2023 & 03678/2023Page 3 of 8
eyes, or difficulty breathing are more serious symptoms and require urgent medical
attention.
In case of accidental contact with eyes, rinse immediately with copious amounts of water.
Accidental spillage on the skin should be washed immediately with soap and water.
In case of accidental self-injection, seek medical advice immediately and show the package
leaflet or the label to the physician.
Special precautions for the protection of the environment:
Not applicable.

Benzylpenicillin is bactericidal. Avoid concurrent use of bactericidal and bacteriostatic
antibiotics.
There is cross-resistance between penicillins and other beta-lactam antibiotics.

Store in a refrigerator (2 °C – 8 °C).
Do not freeze.
Keep the bottle in the outer carton in order to protect from light.

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AN: 03677/2023 & 03678/2023Page 7 of 8

pigs.
To ensure a correct dosage, body weight should be determined as accurately as possible.
Clean the area of the injection site and swab with spirit.
Do not use the same injection site more than once during a course of treatment.
Shake well before use.
The bottle may be broached up to 20 times.
3.10 Symptoms of overdose (and where applicable, emergency procedures and
antidotes)
Penicillin is a compound with a very high therapeutic index.
However, overdosing in young animals and horses should be avoided in order to prevent
procaine poisoning.
3.11 Special restrictions for use and special conditions for use, including restrictions
on the use of antimicrobial and antiparasitic veterinary medicinal products in
order to limit the risk of development of resistance
Not applicable.

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AN: 03677/2023 & 03678/2023Page 5 of 8
3.12 Withdrawal periods
Cattle
Meat and offal: 6 days for treatment duration 3-5 days
8 days for treatment duration 6-7 days
Milk: 4 days (96 hours).
Pigs
Meat and offal: 4 days for treatment duration 3-5 days
6 days for treatment duration 6-7 days
Horses
Meat and offal: 180 days for treatment duration 3-5 days
182 days for treatment duration 6-7 days
Not authorised for use in horses producing milk for human consumption.
4.

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.