Dufamox 15% L.A. Injectable Suspension (Amoxicillin 150mg/ml) – Long-Acting Antibiotic for Cattle, Sheep, Pigs, Dogs & Cats

What Is Dufamox 15% L.A.?

Dufamox 15% L.A. (Long-Acting) is an injectable veterinary antibiotic manufactured by Dutch Farm International, containing amoxicillin trihydrate 150mg per ml (15% w/v) in a sterile oily suspension. The oily vehicle is what makes this a long-acting formulation — it slows the release of amoxicillin from the injection site into the bloodstream, maintaining therapeutic concentrations for up to 48 hours after a single intramuscular injection.

Amoxicillin is a semi-synthetic aminopenicillin antibiotic with broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. It kills bacteria by irreversibly inhibiting the transpeptidase and carboxypeptidase enzymes responsible for cross-linking peptidoglycan chains in the bacterial cell wall, causing osmotic imbalance and cell death during the bacterial growth phase.

Dufamox 15% L.A. is indicated for use in cattle, sheep, goats, pigs, dogs and cats.

Target Bacteria

Dufamox 15% L.A. is active against a wide range of clinically important Gram-positive and Gram-negative pathogens:

• Gram-positive: Actinomyces spp., Bacillus anthracis, Clostridium spp., Corynebacterium spp., Erysipelothrix rhusiopathiae, Listeria monocytogenes, Staphylococcus spp. (penicillinase-negative only), Streptococcus spp.
• Gram-negative: Campylobacter spp., E. coli, Fusobacterium spp., Haemophilus spp., Moraxella spp., Pasteurella spp., Proteus mirabilis, Salmonella spp.

Important: Amoxicillin does NOT act on penicillinase-producing strains (beta-lactamase producers). Bacteria such as penicillinase-forming Klebsiella, Enterobacter, and Pseudomonas are resistant. Where beta-lactamase-producing organisms are suspected, consider a potentiated amoxicillin product (amoxicillin + clavulanic acid) such as Synulox RTU.

Indications by Infection Type

Dufamox 15% L.A. is indicated for treatment of bacterial infections in cattle, sheep, goats, pigs, dogs and cats affecting the following body systems:

• Respiratory tract: pneumonia, bronchopneumonia, bronchitis, rhinitis, tracheitis
• Gastrointestinal tract: enteritis, gastroenteritis, gastroenterocolitis
• Genitourinary tract: metritis, endometritis, cystitis, urethritis, pyelonephritis, mastitis
• Skin and soft tissues: wounds, abscesses, joint infections, umbilical infections, pyoderma, eczema
• Specific conditions: leptospirosis, actinomycosis, erysipelas in pigs, agalactia in sows, parainfluenza, paratyphoid fever

Why Long-Acting? How the Oily Suspension Works

Standard amoxicillin aqueous injections require daily dosing to maintain therapeutic blood levels. Dufamox 15% L.A. uses a micronised amoxicillin trihydrate suspended in an oily vehicle. After intramuscular injection, the oily depot is slowly absorbed from the injection site, continuously releasing amoxicillin into the bloodstream at therapeutic levels for up to 48 hours. This means a single injection every 48 hours is sufficient — significantly reducing handling stress on animals and labour for farmers.

Dosage & Administration

Administer by intramuscular (IM) injection in cattle, sheep, goats and pigs. In dogs and cats, both intramuscular and subcutaneous (SC) administration is acceptable. Do not administer intravenously.

Shake the vial vigorously until a homogeneous suspension is obtained before each use. Use only dry, sterile syringes and needles. Gently massage the injection site after administration to aid absorption.

If no improvement is observed within the first 48 hours, reconsider the diagnosis. Adjust dose in animals with renal impairment. Treatment should continue for at least 48 hours after clinical signs resolve.

Maximum Volume Per Injection Site

If the total required dose exceeds these volumes, split across multiple injection sites in different muscle groups:

• Cattle: maximum 20 ml per injection site
• Pigs: maximum 10 ml per injection site
• Sheep, goats, calves: maximum 5 ml per injection site

Withdrawal Periods

Meat and milk obtained before the specified withdrawal periods must not enter the human food chain. Such milk or meat may be used for animal feeding after consultation with a veterinarian.

Contraindications

• Do not use in animals with known hypersensitivity to amoxicillin, penicillins, or beta-lactam antibiotics
• Do not administer to rabbits, guinea pigs, hamsters or gerbils — aminopenicillins can cause fatal disruption of hindgut flora in these species
• Do not administer intravenously
• Do not use in animals with seriously impaired renal function without dose adjustment
• Do not use to treat infections caused by penicillinase-producing bacteria — amoxicillin will be ineffective; consider Synulox RTU (amoxicillin + clavulanate)
• Prolonged use in ruminants may destabilise ruminal flora — avoid unnecessarily extended courses

Drug Interactions

Dufamox 15% L.A. must not be combined with the following — these cause pharmacological antagonism (bacteriostatic agents block the active bacterial growth phase that amoxicillin requires to be effective):

• Tetracyclines (e.g. oxytetracycline, doxycycline)
• Chloramphenicol
• Macrolides (e.g. tylosin, erythromycin, tilmicosin)
• Lincosamides (e.g. lincomycin, clindamycin)
• Sulfonamides
• Novobiocin and B vitamins (pharmaceutical incompatibility)

Do not mix Dufamox with other drugs in the same syringe.

Side Effects

• Localised swelling, pain or irritation at the injection site (common with oily suspensions)
• Hypersensitivity reactions ranging from mild urticaria to anaphylactic shock in penicillin-sensitive animals — if severe allergic reactions occur, discontinue immediately and administer corticosteroids and adrenaline
• Gastrointestinal disturbance, particularly in herbivores
• Superinfection with non-susceptible organisms after prolonged treatment

Storage & Shelf Life

• Store below 25°C, protected from direct sunlight
• Do not freeze
• Shelf life unopened: 2 years
• After first opening: use within 28 days

Dufamox 15% L.A. vs Other Amoxicillin Products on PetShopBoss

Frequently Asked Questions

What is the dose of Dufamox 15% for cattle?

Cattle receive 1 ml per 10 kg body weight (= 15 mg amoxicillin/kg) by intramuscular injection. For a 500 kg dairy cow, that is 50 ml total, split across multiple injection sites with a maximum of 20 ml per site. Repeat every 48 hours for 3–5 days. The meat withdrawal period is 14 days and milk withdrawal is 60 hours (5 milkings) after the last injection.

Can Dufamox 15% L.A. be used in dogs and cats?

Yes. Dogs and cats receive 1 ml per 10 kg body weight by intramuscular or subcutaneous injection, repeated every 48 hours for 3–5 days. The oily suspension can cause some local irritation at the injection site — massaging gently after administration helps. Oral amoxicillin options such as Clavaseptin tablets may be more practical for long-term outpatient treatment in pets.

Why does Dufamox L.A. only need to be given every 48 hours?

The “L.A.” stands for Long-Acting. Amoxicillin trihydrate is micronised (very finely ground) and suspended in an oily vehicle. After IM injection, the oily depot sits at the injection site and slowly releases amoxicillin into the bloodstream over 48 hours, maintaining therapeutic concentrations without the need for daily injections.

What is the withdrawal period for Dufamox 15% in cattle?

The meat and offal withdrawal period is 14 days after the last injection. The milk withdrawal period is 60 hours (5 milkings) after the last injection. Treated dairy cattle can resume normal milk production for human consumption after this period.

Can Dufamox be used with other antibiotics?

No — amoxicillin must not be combined with bacteriostatic antibiotics including tetracyclines, chloramphenicol, macrolides (tylosin, erythromycin), lincosamides (lincomycin, clindamycin), or sulfonamides. These classes work by stopping bacterial growth, which prevents amoxicillin (which needs actively dividing bacteria to work) from being effective. Do not mix with other drugs in the same syringe.

What is the difference between Dufamox 15% L.A. and Synulox RTU?

Both contain amoxicillin, but Synulox RTU also contains clavulanic acid, which blocks the beta-lactamase enzymes that some bacteria produce to destroy penicillin. Dufamox 15% L.A. is appropriate when the infecting organism is known or likely to be amoxicillin-sensitive. Synulox RTU is preferred when beta-lactamase-producing resistant bacteria are suspected (e.g. resistant Staphylococcus, E. coli, or mixed infections in dogs and cats).

Also available: Synulox RTU 100ml (Amoxicillin + Clavulanate) | Shotapen LA (Benzylpenicillin + Dihydrostreptomycin) 100ml | Draxxin (Tulathromycin) 100ml