POM-V Prescription Required

Virbagest 4 mg/ml Oral Solution for Pigs

Active ingredient: Altrenogest

Form

Liquid

Species

Pigs

Manufacturer

Virbac

VMD MA No.

05653/3032

What it's used for

For the synchronisation of oestrus in nulliparous mature sows.

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 Altrenogest

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

Virbagest 4 mg/ml Oral Solution for Pigs — SPC Details

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

For the synchronisation of oestrus in nulliparous mature sows.

20 mg altrenogest per animal (corresponding to 5 ml of the product per animal) per
day, for 18 consecutive days. Give immediately after mixing with the feed.
The volume to be administered should be measured with an appropriate dosing
device.
Administration:
Animals should be segregated and dosed individually. Add the veterinary medicinal
product as a top-dressing to the feed immediately before feeding.
The synchronisation of oestrus should be supervised by a veterinarian. Nulliparous
mature sows should be segregated not later than 7 days before treatment. During
treatment, animals should not change rooms.
A complete up-take of the medicated feed should be assured.
Most treated gilts will come into oestrus 5 to 6 days after the 18
th
consecutive day of
treatment.

Do not use in boars.
Do not administer to pregnant sows (see section 3.7) or those suffering from uterine
infection.
Do not use in cases of hypersensitivity to the active substance or to any of the
excipients.

Pigs (nulliparous mature sows):
Undetermined frequency
(cannot be estimated from the available
data):
Ovarian cyst
1
Can occur in case of underdosing
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.

Use only in sexually mature gilts that have been in oestrus.

Special precautions for safe use in the target species:
Discard any uneaten medicated feed.
Part-consumed feed must be safely disposed of with other waste feed and not given
to any other animals.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
The veterinary medicinal product should not be administered by pregnant women or
women suspected to be pregnant. Women of childbearing age should handle the
product with extreme care.
The veterinary medicinal product should not be handled by persons with known or
suspected progesterone-dependent tumours or thrombo-embolic disorders.
Direct contact with the skin should be avoided. Personal protective equipment
consisting of gloves and overalls must be worn when handling the veterinary
medicinal product. Porous gloves may let this product pass through. Transcutaneous
absorption may be even higher when the area is covered by an occlusive material,
such as latex or rubber gloves. Accidental spillage on the skin should be washed off
immediately with soap and water. Wash hands after treatment and before meals.
In case of accidental contact with eye, rinse abundantly with water. Seek medical
attention.
Effects of overexposure: Repeated accidental absorption could lead to disruption of
the menstrual cycle, uterine or abdominal cramping, increased or decreased uterine
bleeding, prolongation of pregnancy or headache.
People with known hypersensitivity to the active substance should avoid contact with
the veterinary medicinal product.
Special precautions for the protection of the environment:
When spreading manure from treated animals, the minimum distance to surface
water as defined in the national or local regulations has to be strictly respected,
because the manure may contain altrenogest which could cause adverse effects in
the aquatic environment.

Griseofulvin may alter the effects of altrenogest when administered concurrently with
this veterinary medicinal product.

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

Meat and offal: 9 days.
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.