Shotapen LA Injectable Suspension 100ml – Benzylpenicillin & Dihydrostreptomycin for Cattle, Horses, Pigs, Dogs & Cats

What Is Shotapen LA?

Shotapen LA is a long-acting, ready-to-use injectable antibiotic suspension manufactured by Virbac, combining three active antibiotics in a single formulation: benzathine benzylpenicillin (10g/100ml), procaine benzylpenicillin (10g/100ml), and dihydrostreptomycin sulfate (16.4g/100ml). Together, these deliver a broad-spectrum bactericidal action targeting both Gram-positive and Gram-negative bacteria, with therapeutic concentrations maintained for up to 72 hours after a single IM injection.

Shotapen LA is indicated for cattle, horses, pigs, sheep, goats, dogs and cats — making it one of the most versatile multi-species antibiotics available for both farm livestock and companion animals.

How Shotapen LA Works

Shotapen LA delivers both immediate and prolonged antibiotic action through a dual-mechanism approach:

• Procaine benzylpenicillin is rapidly absorbed after intramuscular injection, reaching peak bactericidal activity within hours and remaining active for 18–24 hours.
• Benzathine benzylpenicillin is slowly released from the injection site, extending effective penicillin G concentrations for 3–5 days in practice.
• Dihydrostreptomycin sulfate is an aminoglycoside antibiotic rapidly absorbed after IM injection, achieving therapeutic levels within 2 hours and maintaining bactericidal activity for 72 hours.

The two antibiotic classes work synergistically: penicillin inhibits bacterial cell wall synthesis by blocking the transpeptidase enzyme responsible for peptidoglycan cross-linking — this directly enhances the penetration of dihydrostreptomycin into bacterial cells, where it binds to ribosome subunits and disrupts protein synthesis. This synergy broadens the spectrum of coverage and slows the development of bacterial resistance.

Target Bacteria

Shotapen LA is active against a wide range of clinically important pathogens, including:

• Gram-positive: Clostridium spp., Corynebacterium spp., Erysipelothrix rhusiopathiae, Staphylococcus spp., Streptococcus spp.
• Gram-negative: Pasteurella spp., Escherichia coli, Salmonella spp., Klebsiella spp., Haemophilus spp., Brucella spp., Campylobacter spp.

Indications by Species

Cattle: Pasteurellosis (pneumonia / shipping fever), septicemia, metritis, leptospirosis, reticulo-peritonitis, mastitis, wound and postpartum infections.

Swine: Septicemia, MMA syndrome (mastitis-metritis-agalactia), erysipelas, leptospirosis, respiratory disease prevention and treatment.

Sheep & Goats: Vesicular stomatitis, arthritis, septicemia, clostridiasis, wound and postpartum infections.

Horses: Bacterial respiratory infections, strangles, wound infections, postoperative treatment.

Dogs & Cats: Bacterial infections of the respiratory tract, genitourinary tract, musculoskeletal system, gastrointestinal tract, and skin/wound infections caused by susceptible organisms.

Dosage & Administration

Administer by intramuscular (IM) injection only. Shake the bottle well before each use. Repeat every 72 hours if required. Treatment should continue for at least 48 hours after symptoms resolve.

Maximum Volume Per Injection Site

• Cattle and horses: 20 ml maximum per injection site
• Pigs: 10 ml maximum per injection site
• Small ruminants and calves: 5 ml maximum per injection site

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

Drug Interactions & Contraindications

Do not use Shotapen LA simultaneously with:

• Aminoglycosides with nephrotoxic/ototoxic effects: neomycin, kanamycin, gentamicin, monomycin
• Macrolide antibiotics (e.g., erythromycin, tylosin)
• Tetracyclines
• Polymyxins
• Lincosamides (e.g., lincomycin, clindamycin)

Contraindicated in: rabbits and small rodents. Do not administer by intravenous (IV) route. Do not use in animals with liver or kidney disease or known hypersensitivity to penicillin. Use with caution in pregnant females — consult your veterinarian before use.

Withdrawal Periods

Milk from treated dairy cows must not be used for human consumption during treatment and for 5 days (10 milkings) after the last injection. It may be used for animal feeding after heat treatment during this period.

Storage & Shelf Life

• Store in a dry, dark place at 15–25°C, away from children
• Alternatively, refrigerate at 2–8°C for extended shelf life
• Unopened shelf life: 12 months at 15–25°C / 18 months at 2–8°C
• After first opening: use within 28 days (store at 5–25°C)
• Shake well before every use — suspension settles on standing

Frequently Asked Questions

What is Shotapen LA used for?

Shotapen LA treats bacterial infections in cattle, horses, pigs, sheep, goats, dogs and cats. Common indications include pneumonia, septicemia, metritis, erysipelas, leptospirosis, mastitis, MMA syndrome in pigs, and wound infections. It is effective against both Gram-positive and Gram-negative bacteria.

How often do you give Shotapen LA?

Shotapen LA is administered every 72 hours (every 3 days). The combination of procaine and benzathine benzylpenicillin together with dihydrostreptomycin maintains therapeutic antibiotic levels for a full 72-hour window after each injection.

What is the correct Shotapen LA dose for cattle?

Cattle receive 5–10 ml per 100 kg body weight by intramuscular injection, repeated every 3 days if necessary. The maximum volume per injection site is 20 ml — if a larger total dose is required, split it across multiple muscle groups.

Can Shotapen LA be used in dogs and cats?

Yes. Dogs and cats receive 1–2 ml per 25 kg body weight by intramuscular injection, every 72 hours. It is effective for respiratory, skin, urinary tract, and wound infections caused by susceptible organisms. Do not use in rabbits or small rodents.

What is the milk withdrawal period for Shotapen LA?

Milk from treated dairy cattle must not enter the human food chain during treatment and for 5 days (10 milkings) after the final injection. The milk can be safely fed to animals after heat treatment during the withdrawal period.

How long does Shotapen LA stay active after injection?

Procaine benzylpenicillin provides immediate activity lasting 18–24 hours. Dihydrostreptomycin is active for 72 hours. The benzathine benzylpenicillin component provides a slow-release effect that can extend coverage to 3–5 days — hence the “long-acting” (LA) designation and the 72-hour repeat dosing interval.

Can Shotapen LA be mixed with other antibiotics?

No. Shotapen LA must not be combined with aminoglycosides (gentamicin, kanamycin, neomycin), macrolides, tetracyclines, polymyxins, or lincosamides. These combinations can cause antagonism, treatment failure, or increased risk of kidney and hearing toxicity from the dihydrostreptomycin component.

What is the slaughter withdrawal for Shotapen LA?

Cattle must not be slaughtered for human consumption until at least 49 days after the last injection. For pigs, the withdrawal period is 30–35 days after the last injection.

Also available: Betamox LA Amoxicillin Injectable 100ml | Tylosin Soluble Powder 50% 100g | Draxxin Injectable 100ml (Tulathromycin)