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  • 2ml Injections with Diluent (Pack of 5) £143.99


This product is sourced in the United Kingdom and is intended for use in the United Kindgom only.

Zylexis is the first product in the UK which has been licensed as an immunmodulator for horses. Zylexis contains an inactivated virus which is unable to cause infection but acts as a super-antigen to boost the horse's immune system. It has been shown to reduce the effects of respiratory disease and improve performance.

Zylexis is provided in a pack of 5 injections (just 2mls each). It is advised to be used at times of stress or crowding. The recommended treatment course is one injection initially, another 2 days later and a final injection 1 week after that. Zylexis should be stored in the fridge and will be sent out in a cold pack.

Need help or advice? Contact us:

  • Landline: 01582 842096
  • Mon - Fri: 8:30am - 5:00pm
  • Sat: 9:00am - 1:00pm (Collections only)
  • Email: [email protected]

All prices include VAT where applicable.

Medication Datasheets

2ml Injections with Diluent (Pack of 5)

Zylexis for Horses


Zylexis for Horses is presented as a lyophilisate and solvent for suspension for intramuscular injection.

Each 2 ml dose contains inactivated Parapoxvirus ovis, strain D1701 that generates a minimum of 460 IFN Units *.

* interferon units as determined in an in vitro stimulation assay in cattle lymphocytes.


Zylexis for Horses acts by stimulation of non-specific immune mechanisms and is of potential clinical value in the reduction of clinical signs of equine respiratory disease associated with stress/crowding.

In a field study, reduction of clinical signs (defined as the first time-point at which significant differences were evident between groups) was shown on day 5 after administration of the full treatment schedule and lasted less than a week.

Dosage and administration

For horses from 10 months of age.

Aseptically reconstitute the lyophilisate with the solvent provided. Shake well before use. The entire contents of the reconstituted vial should be administered intramuscularly as a single dose irrespective of body weight of the animal.

Dosage regimen

Three injections of a single dose for each animal are recommended.

The first two injections are administered with a 48-hour interval (day 0 and day 2) and the 3rd injection is administered on day 9.

To ensure efficacy of the treatment, it is important that the first dose of the product is administered shortly before or up to the day of crowding or exposure to other stressful conditions. It is important that the complete treatment schedule of 3 doses is administered.

Advice on correct administration

Sterile needles and syringes should be used for administration.

Syringes and needles should not have been sterilised chemically or be above ambient temperature. Do not use chemicals to disinfect or sterilise skin.

Shake well before use.

Aseptic precautions should be observed.

Reconstituted vaccine should be used immediately.

Contra-indications, warnings, etc

No local or systemic reactions are expected after the administration of the recommended dose of Zylexis for Horses.

No information is available to support the use of the authorised schedule in pregnant mares. There is no information concerning safety in stallions.

In an overdose (4 ml) safety study carried out in 1 day-old horses, no systemic or local reactions were observed.

If you notice any serious effects or other effects not mentioned in the leaflet, please inform your veterinary surgeon.

All suspected adverse reactions and any suspected lack of efficacy should be reported to the Zoetis UK Ltd technical helpline on 0845 300 8034.

Special precautions for use in animals

The product should not be used for treatment of animals with chronic diseases with unclear causality.

No information is available on the safety and efficacy of this product when used with any other veterinary medicinal product. A decision to use this product before or after any other veterinary medicinal product therefore needs to be made on a case by case basis.

Do not mix with any other veterinary medicinal product.

Withdrawal period

Zero days.

User warnings

In case of accidental self-injection, seek medical advice immediately and show the package leaflet or the label to the physician.

Pharmaceutical precautions

Store in a refrigerator (2°C – 8°C).

Protect from light.

Do not freeze.

Use immediately after reconstitution.

Do not use after the expiry date stated on the label.

Keep out of the sight and reach of children.

For animal treatment only.

Legal category

Packaging quantities

Boxes containing 5 glass vials of lyophilisate together with 5 glass vials of the solvent.

Further information

The exact mechanism of action of inactivated Parapoxvirus ovis is not fully understood but may involve the stimulation and increase of the non-specific immune mechanisms.

In a mouse model, it has been demonstrated that Parapoxvirus ovis induces an autoregulatory cytokine response that involves the up regulation of T helper (Th) 1 type cytokines (IL-12, IL-18, IFNγ) and their subsequent down regulation which is accompanied by induction of IL-4. Furthermore, Parapoxvirus ovis induces phagocytic activity and oxidative burst in various animal species including horses as demonstrated by ex vivo experiments.

In horses, it has been shown that administration of the product stimulates the proliferation of lymphocytes and increases the production of IFNγ in vivo.

It was also shown that administration of the product to horses increases the production of other cytokines such as TNFα, IFN β, IL15 and IL18 in vivo.

This is a limited Marketing Authorisation. A full set of supporting efficacy data is not available for this product


Any unused veterinary medicinal product or waste material should be disposed of in accordance with local requirements.

Marketing Authorisation Number

Vm 42058/4174

Delivery Information

How quickly do you deliver?

Under almost all products on our website is an Estimated dispatch time, check this for a delivery prediction specific to the item you are looking to purchase. These badges are updated live based on the stock levels we have and also those of our suppliers - so are usually very accurate, but cannot be guaranteed. In more general terms, we aim to dispatch all orders within 1 working day of receiving payment (and a prescription if required). If we cannot do so within 3 working days we will contact you by email.

What do you charge for delivery?

For UK delivery, we charge the following:

Order Total Weight Delivery
£0-£28.99 Under 2kg £2.99
2kg+ £4.99
£29-£38.99 Under 2kg Free
2kg+ £4.99
£39+ Under 2kg Free
2kg+ Free

Prices quoted are for delivery to all parts of mainland UK except certain Scottish postcodes (where the price is higher for items sent by courier. Delivery of food abroad (including Channel Islands, N. Ireland and other islands around the UK) is charged at a higher price and free delivery is not available. Temperature controlled products, such as Insulin, are also not always subject to the standard and/or free delivery options.

For full information on our delivery charges, including prices on heavy deliveries to Scotland and abroad, see our delivery information page.

We can deliver most items to all around the world, but prices do vary. To find the exact cost of shipping your item, and to see all options available, follow these steps:

  1. Put the items you wish to order in your basket
  2. Proceed to checkout and enter your delivery address, including country
  3. Delivery information including price will automatically update to what is available to you

Delivery of aerosols

Due to restrictions aerosols can't be sent by Royal Mail. We appreciate your understanding.

Delivery of temperature controlled items

Some products, such as insulin and frozen food, need to be delivered in insulated packaging to prevent them from getting too warm (or too cold) during transit from us to you. Purchasing any of these items in your order will result in a £1.99 charge being added to the total to cover the high cost of the insulated packaging materials. You only pay the £1.99 once per order, regardless of how many temperature controlled items you purchase in that order.

How do I cancel or return an order?

Please call us as soon as possible if you need to amend or cancel an order on 01582 842096. If your order has been processed for dispatch we will be unable to cancel or amend the order. You will however be able to return your product for a full refund*.

To return an item, you must contact us by phone or email to arrange this BEFORE posting any product back to us. We will explain the process at this stage for you.

*For full details on returns, see our terms and conditions page.


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