This product is a long-acting sulfonamide drug. It has antibacterial effects on non-enzyme-producing Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Escherichia coli, Klebsiella, Salmonella, Shigella and other Enterobacteriaceae, Neisseria gonorrhoeae, Neisseria meningitidis, and Haemophilus influenzae. Sulfonamide drugs are broad-spectrum antibacterial agents. Their mechanism of action is that they are similar in structure to para-aminobenzoic acid (PABA) and can compete with PABA for dihydrofolate synthase in bacteria, thereby preventing PABA from synthesizing folic acid required by bacteria as a raw material and reducing the amount of metabolically active tetrahydrofolate, which is an essential substance for bacteria to synthesize purines, thymine nucleotides and deoxyribonucleic acid (DNA), thereby inhibiting the growth and reproduction of bacteria.

It has a broad-spectrum antimicrobial effect in vitro, including aerobic Gram-negative and Gram-positive bacteria, anaerobes, Rickettsia, spirochetes and Chlamydia. It has a bactericidal effect on Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis; it only has an antibacterial effect on anaerobic bacteria such as Staphylococcus aureus, Streptococcus pyogenes, Streptococcus viridans, Group B hemolytic Streptococcus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella typhi, Salmonella paratyphi, Shigella, Bacteroides fragilis, etc. Pseudomonas aeruginosa, Acinetobacter, Enterobacter, Serratia marcescens, indole-positive Proteus, methicillin-resistant Staphylococcus and Enterococcus are usually resistant to chloramphenicol. Chloramphenicol is fat-soluble, enters bacterial cells by diffusion, and reversibly binds to the 50S subunit of bacterial ribosomes, inhibiting the formation of peptide chains, thereby preventing protein synthesis.

This product belongs to the tetracycline antibiotics, and is sensitive to many Rickettsia, Mycoplasma, Chlamydia, some atypical mycobacteria, and spirochetes. Actinomycetes, Bacillus anthracis, Listeria monocytogenes, Clostridium, Nocardia, Vibrio, Brucella, Campylobacter, Yersinia, etc. are sensitive to this product. It has certain antibacterial activity against Neisseria gonorrhoeae, but penicillin-resistant gonococci are also resistant to methacycline. Common clinical pathogens such as gram-positive bacteria such as Staphylococcus and most Enterobacteriaceae are resistant to methacycline. There is cross-resistance between this product and different varieties of tetracyclines.

This product is a first-generation cephalosporin, which has good antibacterial effect on some strains of Gram-positive cocci such as non-penicillinase-producing and penicillinase-producing Staphylococcus aureus, coagulase-negative Staphylococcus, group A hemolytic Streptococcus, Streptococcus pneumoniae and viridans Streptococcus. Anaerobic Gram-positive bacteria are mostly sensitive to this product, while Bacteroides fragilis is resistant to it. Methicillin-resistant Staphylococci and Enterococci are resistant to this product. The effect of this product on Gram-positive and Gram-negative bacteria is similar to that of cephalexin. This product has a certain effect on Neisseria gonorrhoeae, and is also active against enzyme-producing Neisseria gonorrhoeae; its activity against Haemophilus influenzae is poor.

This product is a broad-spectrum antibacterial agent, with bactericidal effect at high concentrations. It has antibacterial effects on Streptococcus pneumoniae, hemolytic Streptococcus, Streptococcus viridans and some Staphylococci, Clostridium perfringens, Bacillus anthracis, Yersinia pestis, Corynebacterium diphtheriae, Clostridium tetani, Brucella, Haemophilus influenzae, Campylobacter, Vibrio cholerae, etc. It also has inhibitory effects on Rickettsia, Mycoplasma, Chlamydia, Spirochete, and some protozoa. It has better effects on Gram-positive bacteria than Gram-negative bacteria, but Enterococcus is resistant to it. The mechanism of action is that the drug can specifically bind to the A position of the 30S subunit of the bacterial ribosome, preventing the connection of aminoacyl-tRNA at this position, thereby inhibiting the growth of peptide linkage and affecting the synthesis of bacterial proteins.