POM-V Prescription Required

Virbagest 4 mg/ml Oral Solution for Pigs

Active ingredient: Altrenogest

Form

Liquid

Species

Pigs

Manufacturer

Virbac

VMD MA No.

05653/5063

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 26 Mar 2026.

For the synchronisation of oestrus in nulliparous mature sows.

For oral use as a top-dressing.
20 mg altrenogest per animal and per day, for 18 consecutive days, corresponding to
5 ml of the product per day and per animal for 18 consecutive days given orally with
feed for immediate consumption.
The volume to be administered should be measured with an appropriate dosing
device.
Administration:
Animals should be segregated and dosed individually. Add the product as a top
dressing to the feed immediately before feeding.
disposed of with other waste feed and not given to other animals.
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 the room.
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 4.7) or those suffering from uterine
infection.
Do not use in case of hypersensitivity to the active substance.

Under dosing can lead to the formation of cystic follicles.

Revised: March 2025
MA split from NI following AN: 03215/2023

None.

Revised: March 2025
MA split from NI following AN: 03215/2023

Special precautions for use in animals
Ensure the correct dose is administered daily as under dosing can lead to the
formation of cystic follicles.
Add the veterinary medicinal product to the feed immediately before feeding. Discard
any uneaten medicated feed.
Use only in sexually mature gilts that have been in oestrus.
Part consumed feed must be safely disposed of and not given to any other animal.
Special precautions to be taken by the person administering the veterinary
medicinal product to animals
Women who are pregnant, or suspected to be pregnant, should not use the product.
Women of childbearing age should handle the product with extreme care. The
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 clothing (gloves
and overalls) must be worn when handling the 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. Get 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.
Other precautions regarding impact on 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 product.

Meat and offal: 9 days.
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.