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Amfipen LA 100mg/ml Antibiotic Injection

Amfipen LA 100mg/ml Antibiotic Injection

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  • 80ml Bottle £16.49


Amfipen LA 100mg/ml is an injectable antibiotic containing ampicillin in a formulation designed to give at least 48 hours cover from a single injection. It can be used in dogs, cats, cattle, pigs and sheep for infections sensitive to ampicillin. It is not suitable for use in horses due to the localised reaction which develops around the injection site. It should not be used in small herbivores due to the risk of serious digestive upset.

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Medication Datasheets

80ml Bottle

Amfipen LA 100 mg/ml suspension for injection

Qualitative and quantitative composition

Active substance:

Each ml contains:

Ampicillin (as anhydrous ampicillin) 100 mg


Dodecyl gallate 87.5 µg/ml

For the full list of excipients, see section “Pharmaceutical particulars”.

Pharmaceutical form

Suspension for injection. White to off white suspension

Clinical particulars

Target species

Cattle, sheep, pigs, dogs and cats.

Indications for use

Amfipen LA is indicated for treatment of diseases or secondary infections due to the following bacteria sensitive to ampicillin in dogs, cats, cattle, sheep and pigs and where prolongation of activity from a single injection is required: Streptococcus spp., Trueperella pyogenes, Mannheimia haemolytica, Pasteurella multocida, Erysipelothrix rhusiopathiae, Staphylococcus aureus and Staphylococcus species.


Do not use in case of hypersensitivity to the active substance, or to any of the excipients.

Do not administer to rabbits, hamsters or guinea pigs. Not effective against beta-lactamase producing organisms.

Do not use this product in horses due to the likelihood of severe local reaction at the injection site.

Do not inject dogs and cats intramuscularly.

Do not use in animals producing milk for human consumption.

Special warnings for each target species

Severe disturbances of the intestinal bacterial flora of herbivores may occur.

Special precautions for use

Whenever possible, the product should only be used based on susceptibility testing.

Official and local antimicrobial policies should be taken into account when the product is used.

Use of the product deviating from the instructions given in the SPC may increase the prevalence of bacteria resistant to ampicillin and may decrease the effectiveness of treatment with other beta-lactams due to the potential for cross-resistance.

Operator warnings

Penicillin and cephalosporins may cause hypersensitivity (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 may occasionally be serious.

1. Do not handle this product if you know you are sensitised or if you have been advised not to work with such preparations.

2. Handle this product with great care to avoid exposure, taking all recommended precautions.

3. If you develop symptoms following exposure, such as a skin rash, you should seek medical advice and show the doctor this warning. Swelling of the face, lips or eyes or difficulty with breathing are more serious symptoms and require urgent medical attention.

Care should be taken to avoid accidental self-injection. In case of accidental self-injection, seek medical advice immediately. Wash hands after use.

Adverse reactions

Severe disturbances of the intestinal bacterial flora of herbivores may occur.

Allergies to ampicillin can occur rarely. Local swelling at the injection site may occur in dogs, this usually regresses spontaneously in 2-4 days.

Use during pregnancy, lactation or lay

No special precautions necessary.


Bacteria, particularly gram-negative organisms, that show a cross-resistance with other ß lactam antibiotics may show resistance.

There is antagonism between this product and antibiotics with bacteriostatic activity.

Amounts to be administered and administration route


Cattle and sheep 15 mg/kg, pigs 25 mg/kg by intramuscular route.

Dogs 15 mg/kg, cats 20 mg/kg by subcutaneous route.


Cow 500 kg 75 ml
Sheep 50 kg 7.5 ml
Pig 50 kg 12.5 ml
Dog 10 kg 1.5 ml
Cat 5 kg 1 ml

Shake well before use. Clean the area of the injection site and swab with spirit. This product does not contain an antimicrobial preservative.

Only dry sterile needles and syringes should be used for administration and the septum should be swabbed before removing each dose. Do not use the same injection site more than once during a course of treatment. Do not administer more than 10 ml per injection site in pigs and sheep and 20 ml in cattle. Treatment may be repeated once after 48 hours.

To ensure a correct dosage, body weight should be determined as accurately as possible to avoid under dosing.


Ampicillin is a compound with a very high therapeutic ratio. It is unlikely that an overdose of Amfipen LA will have adverse effects on the treated animal. No specific antidote or treatment is recommended.

Withdrawal periods

Meat and offal

Cattle, pigs and sheep: 60 days

Not authorised for use in animals producing milk for human consumption.

Pharmacological particulars

Pharmacotherapeutic group

Antibacterials for systemic use, β-lactam antibacterials, enicillins, penicillins with extended spectrum.

ATC Vet Code: QJ01CA01

Pharmacodynamic properties

Ampicillin is a beta-lactam antibiotic which has bactericidal activity against mainly Gram-positive bacteria and some Gram-negative aerobes. It is sensitive to beta-lactamase (penicillinase) inactivation. It is widely distributed in the extracellular fluids after absorption, and eliminated almost entirely by the kidneys.

Bioavailability studies indicate that a minimum duration of activity of 48 hours can be expected following a single injection.

Pharmacokinetic properties

Amfipen LA, containing ampicillin anhydrate in a long acting base, has been especially developed to overcome the disadvantage of frequent administrations required for short-acting ampicillin formulations. Blood level studies clearly show that the injection interval can be extended to at least 48 hours instead of the usual 12-24 hours.

After an initial peak at one hour after injection, the ampicillin concentrations decline slowly and gradually over the 48 hour period and 34 to 50 % of the ampicillin becomes available on the second day after injection.

Animal studies have demonstrated that ampicillin is evenly distributed throughout the body tissues and is concentrated in the liver and the kidneys. It is excreted unchanged in the urine. Investigations have shown that ampicillin is excreted in high concentration in the bile.

Pharmaceutical particulars


Dodecyl gallate, Aluminium monostearate and Fractionated coconut oil.

Major incompatibilities

Do not mix with any other veterinary medicinal product.

Shelf life

Shelf life of the veterinary medicinal product as packaged for sale: 3 years.

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

Special precautions for storage

Do not store above 25 °C. Do not freeze.

Immediate packaging

Type II (Ph Eur) glass vials closed with halogenated butyl rubber stoppers or PET vials closed with halogenated butyl rubber stoppers. The both types of vial are sealed with an aluminium cap. The vials contain 80 ml of product.

Not all pack sizes may be marketed


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

Marketing Authorisation Number

Vm 01708/4233

Date of the first authorisation or date of renewal

29 August 2001.

Date of revision of the text

March 2016.

Any other information

For animal treatment only. Keep out of the sight and reach of children.

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.


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