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GastroGard for Horses

GastroGard for Horses
37% Oral Paste » Pack of 14 Syringes

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  • 37% Oral Paste » Pack of 14 Syringes £259.98
  • 37% Oral Paste » Single Syringe £19.93

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GastroGard is used to treat equine stomach ulceration. It is supplied by syringe to be dosed directly into the horse's mouth. The plunger is graduated and has a mechanism to deliver the correct dose according to the bodyweight of the horse. One dose is normally given every day for a month to treat the problem, then a further month at a quarter of the dose rate to prevent recurrence. Stomach ulceration in the horse is best monitored by gastroscopy. GastroGard can be used in foals from 4 weeks of age. Sometimes the lower dose rate is used as a preventative in situations where ulceration has not yet occurred, but is judged to be a significant risk. Contains Omeprazole.

GastroGard side effects are very uncommon. It is not recommended for use in pregnant mares and should be used with caution in horses on warfarin. (A lower dose of warfarin might be needed.)

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Medication Datasheets

37% Oral Paste » Single Syringe

GastroGard 370 mg/g oral paste

Qualitative and quantitative composition

Each gram contains:

Active substance: Omeprazole 370 mg

Excipient: Yellow iron oxide (E172) 2 mg

For the full list of excipients, see below.

Pharmaceutical form

Oral paste. Smooth homogeneous yellow to yellow-tan paste.

Clinical particulars

Target species


Indications for use

For treatment and prevention of gastric ulcers.


Do not use in mares producing milk for human consumption.

Special warnings for each target species


Special precautions for use in animals

Not recommended for animals under 4 weeks of age or weighing less than 70 kg bodyweight. Stress (including high performance training and competition), feeding, management and husbandry practices may be associated with the development of gastric ulceration in horses. Individuals responsible for the well-being of horses should consider reducing the ulcerogenic challenge by modifying husbandry practices to achieve one or more of the following: reduced stress, reduced fasting, increased intake of roughage and access to grazing.

Special precautions to be taken by the person administering the product to animals

As this product may cause hypersensitivity, avoid direct contact with skin and eyes. Use impervious gloves and do not eat or drink when handling and administering the product. Wash hands or any exposed skin after use. In case of contact with eyes, wash immediately with clean running water and seek medical advice. Persons developing a reaction after contact with the product should avoid handling the product in future.

Adverse reactions

There are no known treatment-related clinical adverse effects.

Use during pregnancy, lactation or lay

In the absence of data during pregnancy and lactation, the use of GastroGard in pregnant and lactating mares is not recommended.


Omeprazole may delay the elimination of warfarin. No other interaction with medicines routinely used in the treatment of horses is expected, although interaction with drugs metabolised by liver enzymes cannot be excluded.

Amounts to be administered and administration route

GastroGard is effective in horses of various breeds and under different management conditions; foals as young as four weeks and weighing over 70 kg; and breeding stallions.

For oral administration.

Treatment of gastric ulcers: One administration per day during 28 consecutive days at the dose rate of 4 mg omeprazole per kg bodyweight followed immediately by a dosage regimen of one administration per day during 28 consecutive days at the dose rate of 1 mg omeprazole per kg bodyweight, to reduce the recurrence of gastric ulcers during treatment. Should recurrence occur, re-treatment at a dose rate of 4 mg omeprazole per kg body weight is recommended.

It is recommended that treatment is combined with changes of husbandry and training practices (please see Special precautions for use in animals).

Prevention of gastric ulcers: One administration per day at the dose rate of 1 mg omeprazole per kg bodyweight.

To deliver GastroGard at the dose of 4 mg omeprazole/kg, set the syringe plunger to the appropriate dose division for the horse’s weight. Each full dose division on the syringe plunger delivers sufficient omeprazole to treat 100 kg bodyweight. The contents of one syringe will treat a 575 kg horse at the rate of 4 mg omeprazole per kg bodyweight.

To deliver GastroGard at the dose of 1 mg omeprazole/kg, set the syringe plunger to the dose division equivalent to one quarter of the horse’s bodyweight. At this dose, each full dose division on the syringe plunger will deliver sufficient omeprazole to treat 400 kg body weight. For example, to treat a horse weighing 400 kg, set the plunger to 100 kg.

Replace cap after use.


No undesirable effects related to treatment were observed following daily use for 91 days at omeprazole dosages up to 20 mg/kg in adult horses and in foals older than 2 months.

No undesirable effects related to treatment (in particular no adverse effect on the semen quality or reproductive behaviour) were observed following daily use for 71 days at an omeprazole dosage of 12 mg/kg in breeding stallions.

No undesirable effects related to treatment were observed following daily use for 21 days at an omeprazole dosage of 40 mg/kg in adult horses.

Withdrawal periods

Meat and offal: 1 day. Not permitted for use in mares producing milk for human consumption.

Pharmacological particulars

Pharmacotherapeutic group

Drugs for peptic ulcer, Proton pump inhibitors.

ATCvet code: QA02BC01

In studies lasting up to 28 days, treatment with GastroGard at the dose rate of 1 mg omeprazole per kg body weight per day has been shown to help prevent the occurrence of gastric ulcers in horses exposed to ulcerogenic conditions.

Omeprazole is a proton pump inhibitor belonging to the substituted benzimidazole class of compounds. It is an antacid, for treatment of peptic ulcers.

Omeprazole suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase enzyme system at the secretory surface of the parietal cell. The H+/K+- ATPase enzyme system is the acid (proton) pump within the gastric mucosa. Because H+/K+- ATPase is the final step involved in control of acid secretion, omeprazole blocks secretion irrespective of the stimulus. Omeprazole irreversibly binds to the gastric parietal cell H+/K+-ATPase enzyme that pumps hydrogen ions into the lumen of the stomach in exchange for potassium ions.

At 8, 16 and 24 hours after dosing horses with omeprazole at 4 mg/kg/day orally, pentagastrin-stimulated gastric acid secretion was inhibited by 99%, 95% and 90% and basal secretion was inhibited by 99%, 90% and 83%.The full effect on the inhibition of acid secretion is reached by five days after the first administration.

Pharmaceutical particulars


Yellow iron oxide (E172), Monoethanolamine, Potassium sorbate, Cassia oil, Sodium stearate, Calcium stearate, Hydrogenated castor oil, Propylene glycol octanoate decanoate, Sesame oil.

Major incompatibilities

Not applicable.

Shelf life

Shelf life of the product as packaged for sale: 18 months.

Shelf life after first opening the immediate packaging: 28 days.

Special precautions for storage

Do not store above 30 °C. Replace cap after use.

Immediate packaging

Carton box of 1, 7 or 14 syringes.


Any unused product or waste materials derived from such products should be disposed of in accordance with local requirements.

Marketing Authorisation Number

Vm 08327/4205

Legal category

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.

Reviews (8)

Q & A

Below are some recent questions we've received regarding GastroGard for Horses, including answers from our team.

10 June 2015 at 12:49pm



  • VioVet customer since 2014
  • From: Midlothian, United Kingdom

Can I please check dosage rate - is it one syringe a day typically?

  • Non-Executive Director

This depends on the size of the horse and the reason for giving the product. You always give a dose once per day. This is one syringe per day for a horse weighing 575kg to be treated for gastric ulceration. The syringes are graduated so that you can give less for a smaller horse's weight. If you are giving it as a preventative then you give a quarter dose once per day, so any horse would only need part of a syringe. There is a way of giving the correct amount as long as you know the weight of your horse.

19 April 2015 at 7:54pm

Do I need a prescription?


My horse exhibits all the signs of gastric ulcers, poor performance, right hind turned out and tries to kick you if you touch his stomach on the right hand side in front of the stifle and girthing has become dangerous with being bitten and kicked. He was scoped a year ago and no ulcers were found. He has since had periods of box rest and limited turnout and the above behaviour has been a result of this. My question is, do I need a prescription to use this product? I've tried many others with some success but the problems never go away. Help!

  • Non-Executive Director

GastroGard is indeed a prescription product. You need to talk to your vet and see if he agrees. If so then send us a prescription with your order and we can then supply the GastroGard.