Introduction: Amoxicillin, as one of the most commonly used drugs in pig farming, is reflexively and promptly administered by farmers to pigs showing signs of inflammation. However, prolonged use has led to a loss of confidence among farmers, primarily due to either a perceived decline in the drug's quality or increased pathogen resistance. To enhance the effectiveness of veterinary drugs without increasing costs, understanding drug compatibility techniques and their underlying mechanisms is crucial. Below, I'll briefly explain this issue:

1. Drugs that can be combined with veterinary amoxicillin and their synergistic mechanisms: Amoxicillin is a fast-acting bactericidal antibiotic that targets the bacterial cell wall during the replication phase, leading to bacterial lysis and exerting its antibacterial effect. The veterinary drugs that enhance its effectiveness through combination include:

   • Bactericidal antibiotics effective during stationary phase: Primarily aminoglycosides such as neomycin sulfate, kanamycin sulfate, kanamycin, and ampicillin sulfate. These drugs synergistically enhance antibacterial effects through complementary antibacterial mechanisms, thereby achieving a synergistic effect greater than the sum of their parts.
   • Drugs damaging bacterial cell membranes: Mainly colistin sulfate: Colistin sulfate damages bacterial cell membranes, while amoxicillin damages bacterial cell walls. Their combined use synergistically enhances antibacterial effects through multi-site action, achieving a synergistic effect greater than the sum of their parts.
   • Others: Mainly quinolones such as enrofloxacin and ciprofloxacin. Quinolones inhibit bacterial DNA synthesis, exhibiting potent antibacterial effects and low resistance. Their combined use complements antibacterial mechanisms, also achieving a good synergistic effect greater than the sum of their parts.

2. Detailed explanation of the drug combination scheme between veterinary amoxicillin and colistin sulfate: Understanding the combination of drugs is just the first step in formulating a treatment plan. More importantly, understanding the proper proportions of the combined veterinary drugs is crucial to enhancing antibacterial effects without increasing drug costs. Relevant medication formulas include:

   • Veterinary amoxicillin colistin sulfate 400 grams + 10% compound amoxicillin 50 grams + 10% ampicillin sulfate 100 grams, all soluble powders, recommended dosage added 0.3-0.5g/L water.
   • 30% amoxicillin (3 kg water / 1 g drug) + 10% colistin sulfate (1 kg water / 3 g drug), with drug dosage halved during the second administration.

   Application scenarios in pig farming:

   • Yellow-white dysentery, paratyphoid and diarrhea, peritonitis, and urinary system inflammation caused by E. coli, Salmonella infections.
   • Pig arthritis, soft tissue infections, and peritonitis caused by Streptococcus suis and Haemophilus parasuis infections.
   • Respiratory tract inflammation in pigs caused by Bordetella bronchiseptica and Actinobacillus pleuropneumoniae infections.

   Amoxicillin is a commonly used veterinary drug often combined with other drugs to enhance therapeutic efficacy. Here are some optimal combinations for amoxicillin:

   • Amoxicillin + clavulanic acid: Clavulanic acid, a common β-lactamase inhibitor, irreversibly binds to β-lactamases produced by bacteria, blocking their ability to degrade amoxicillin's β-lactam ring, thereby synergistically enhancing efficacy and preventing bacterial resistance.
   • Amoxicillin + colistin sulfate
   • Amoxicillin + enrofloxacin
   • Amoxicillin + kanamycin: Kanamycin belongs to the same class of drugs (aminoglycosides) with the broadest spectrum and strongest antibacterial activity among aminoglycoside antibiotics, used in combination with amoxicillin.

   It's important to note that different combinations may be suitable for different diseases and animal species, and specific usage and dosages may vary due to individual differences. Before using any veterinary drug, it is essential to consult a professional veterinarian to ensure safety and effectiveness.