The role and efficacy of veterinary drug neomycin sulfate
Neomycin sulfate is an aminoglycoside antibiotic. This product has good antibacterial effect on Staphylococcus (methicillin-sensitive strain)
Neomycin sulfate is an aminoglycoside antibiotic. This product has good antibacterial effect on Staphylococcus (methicillin-sensitive strain), Corynebacterium, Escherichia coli, Klebsiella, Proteus and other Enterobacteriaceae bacteria, and has good antibacterial effect on various groups of Streptococcus, Streptococcus Coccus, Enterococcus, etc. have poor activity. Pseudomonas aeruginosa, anaerobic bacteria, etc. are resistant to this product. Bacteria have partial or complete cross-resistance to streptomycin, neomycin, kanamycin, and gentamicin. Systemic administration of neomycin has significant nephrotoxicity and ototoxicity, so it is currently limited to oral or topical application.
The reason why neomycin sulfate is favored by veterinarians and breeders is mainly because of the following two species advantages.
1. The first choice of enteric drugs for antibiotic-free breeding.
For the treatment of poultry, the drug withdrawal period is only 5 days; and after 5 days of drug withdrawal, there is almost no drug residue in the muscle (understandable as no resistance).
2. It is efficient and economical for the treatment of various intestinal diseases.
It is mainly reflected in the "high-efficiency" treatment under the condition of scientific and skillful use and reasonable compatibility, and the "economy" that the drug itself is relatively cheap and the effective dosage is small.
So, how to use good-quality neomycin sulfate to achieve "high-efficiency" therapeutic effect?
This requires an understanding of the pharmacology and antibacterial spectrum of neomycin sulfate, because beyond its effective action and pathogenic spectrum, no matter how good the drug is, it will be ineffective.
Neomycin sulfate is administered orally to livestock and poultry, and under normal circumstances it is rarely absorbed (within 5%). However, if a large dose is taken orally continuously, especially when there is ulcer or inflammation in the intestinal mucosa, the gastrointestinal tract of livestock and poultry can still absorb a considerable amount of neomycin sulfate. Especially when the renal function of livestock and poultry is impaired, the excretion of neomycin sulfate entering the body slows down, and the blood drug concentration in the body can increase significantly at this time.
For grass-roots veterinarians and first-line drug users, remember not to use neomycin sulfate for systemic administration by injection, because neomycin sulfate administered by injection has significant nephrotoxicity, so neomycin sulfate is currently limited to oral administration, and oral administration Effectiveness and safety have been used in livestock and poultry clinics for 60 to 70 years.
It is a commonly used medicine. However, many people have not used the effect of this medicine and used it "highly effective".
The key issue is: when you use neomycin sulfate veterinary drug products, you must use them in combination, and at least two or more drugs should be used in combination when writing a prescription.
In the treatment of enteritis-type E. coli, macrocyclic drugs such as neomycin with erythromycin thiocyanate, tylosin tartrate or tilmicosin solution are used. Because when neomycin sulfate is shared with macrocyclic drugs, there will be a synergistic effect between them to increase the drug effect; at this time, if TMP synergist is added, the effect will come faster.
Specific to how to determine the actual clinical formula, the effective therapeutic dosage of neomycin sulfate is to mix 1g of neomycin sulfate with 8~10 catties of water; for the above-mentioned macrocyclic drugs, the effective dosage of TMP is mixed with 1 g of water and 10~15 catties of water. The calculation method is the sum of the two drugs, and the synergy is calculated according to the drug susceptibility test 3:1, 4:1 or 5:1!
Of course, the above-mentioned knowledge and usage skills of neomycin sulfate are only a small part.
The relatively unique bactericidal mechanism and target of neomycin sulfate make it basically non-existent pharmacological incompatibility with common anti-infective drugs in veterinary clinics. Only in terms of physical and chemical effects, neomycin sulfate reacts with cephalosporin anti-infective drugs, and they need to be used separately when they are administered.
After oral administration of neomycin sulfate to chickens, it is rarely absorbed by the gastrointestinal tract. Especially in the intact state of the intestinal mucosa, the total amount of neomycin sulfate absorbed into the blood through oral administration is less than 5% of the total dose.
However, once the mucous membrane of the digestive tract is ulcerated, or the epidermis is peeled off, or the mucous membrane of the digestive tract is inflamed, etc., a maximum of 20% of the oral administration of neomycin sulfate will pass through the digestive system with significantly increased permeability. It enters the internal circulation of the body and is distributed to tissues and organs such as the liver, kidney, heart, lung and abdominal cavity.
Neomycin sulfate absorbed into the body is mostly concentrated in nucleated cells, especially in white blood cells. Most of it is quickly excreted through the kidneys. However, if renal insufficiency occurs, the excretion of neomycin sulfate will be blocked and slowed down; most of the unabsorbed neomycin sulfate will be excreted with feces. Within 24 hours, about 12% to 25% of the neomycin sulfate absorbed into the body is excreted by the kidneys, and about 50% to 90% are excreted by the bile.
In terms of antibacterial spectrum, neomycin sulfate has the best effect on Gram-negative bacteria, especially Escherichia coli and Salmonella; large doses of neomycin sulfate also have a good effect on Mycoplasma gallinarum Effect. However, increasing the dose of the drug will significantly reduce the economic value of the drug, and will also increase the probability of adverse reactions. Therefore, in addition to the use of macrolides in the clinical treatment of mycoplasma in veterinary medicine; in foreign countries, more spectinomycin is used.
However, the combined administration of neomycin sulfate and antibiotics such as penicillins, cephalosporins, sandacins, fosfomycins, tetracyclines, macrolides, etc., is more difficult for severe bacterial systemic infections and It has higher, better and more economical application value than neomycin sulfate alone, especially when combined with some synergists such as clavulanate potassium, trimethoprim, and sulbactam. This is the main reason why we advocate new uses of old medicines.