Neomycin sulfate is an aminoglycoside antibiotic. The product has good antibacterial effect on Staphylococcus (methicillin sensitive strain), Corynebacterium, Escherichia coli, Klebsiella, Proteus and other Enterobacteriaceae, but has poor activity on Streptococcus, Streptococcus pneumoniae and Enterococcus. Pseudomonas aeruginosa and anaerobic bacteria are resistant to this product. Bacteria have partial or complete cross resistance to streptomycin, neomycin, kanamycin and gentamicin. Systemic neomycin has significant nephrotoxicity and ototoxicity, so it is limited to oral or local application.
Neomycin sulfate is favored by veterinarians and farmers mainly because of the following two species advantages.
No anti intestinal drugs are preferred.
For the treatment of poultry, the withdrawal period is only 5 days; And after 5 days of drug withdrawal, there was almost no drug residue in the muscle (which can be understood as no anti-inflammatory).
The treatment of various intestinal diseases is efficient and economical.
It is mainly reflected in the "efficient" treatment under the conditions of scientific and ingenious use and reasonable compatibility, as well as the "economy" of relatively cheap drugs and small effective dosage.
So, how to make good use of neomycin sulfate with good quality and produce "efficient" therapeutic effect?
This requires understanding the pharmacology and antibacterial spectrum of neomycin sulfate, because beyond its effective effect and pathogenic spectrum, the best drug will be ineffective.
Neomycin sulfate is administered orally to livestock and poultry. Under normal circumstances, it is rarely absorbed (within 5%). However, if a large dose is taken orally continuously, especially when the intestinal mucosa has ulcer or inflammation, the gastrointestinal tract of livestock and poultry can still absorb neomycin sulfate in a considerable amount. Especially when the renal function of livestock and poultry decreases, the excretion of neomycin sulfate into the body slows down, and the blood drug concentration in the body can increase significantly.
For grass-roots veterinarians and first-line drug users, remember not to inject neomycin sulfate into the whole body, because neomycin sulfate injected has significant nephrotoxicity, so neomycin sulfate is currently limited to oral administration, and the effectiveness and safety of oral administration have been used in livestock and poultry clinic for 60 or 70 years.
It is a commonly used medicine. However, many people fail to use the effect of this medicine and use it "efficiently".
The key problem is: when using neomycin sulfate veterinary drug products, we must be combined with more than two drugs when prescribing.
In the treatment of enteric Escherichia coli, neomycin is used with macrocyclic drugs such as erythromycin thiocyanate, tylosin tartrate or tilmicosin solution. Because when neomycin sulfate is shared with macrocyclic drugs, there will be synergy between them, which can increase the efficacy; At this time, if TMP synergist is added, the effect will be faster.
Specific to how to determine the actual clinical formula, the effective therapeutic dosage of neomycin sulfate is 8 ~ 10 kg of 1G neomycin sulfate mixed with water; For the above macrocyclic drugs, 1g of water is mixed with 10 ~ 15kg of water; The calculation method of TMP effective dosage is the sum of the two drugs, and the synergistic effect is calculated according to drug sensitivity test 3:1, 4:1 or 5:1!
Of course, the above knowledge and skills of neomycin sulfate are only a small part.
Neomycin sulfate has a unique bactericidal mechanism and action target, which makes it basically have no pharmacological incompatibility with common anti infective drugs in veterinary clinic. Only in terms of physical and chemical effects, neomycin sulfate reacts with cephalosporins, which need to be used separately when administered.
Neomycin sulfate is rarely absorbed by gastrointestinal tract after oral administration to chickens. Especially when the intestinal mucosa is intact, the total amount of neomycin sulfate absorbed into the blood by oral administration is less than 5% of the total dosage.
However, in case of ulcer of digestive tract mucosa, peeling of epidermis, inflammation of digestive tract mucosa and other incomplete mucosa, up to 20% neomycin sulfate can be taken orally, which will enter the internal circulation through the digestive tract mucosa with significantly increased permeability and be transmitted to the liver, kidney, heart, lung, abdominal cavity and other tissues and organs.
The concentration of neomycin is the highest in multinucleated cells, especially in leukocytes. Most are quickly excreted through the kidneys. However, if the renal function is not complete, the excretion of neomycin sulfate will be blocked and slow down; Those neomycin sulfate, most of which are not absorbed, will be excreted with feces. Within 24 hours, about 12% ~ 25% of neomycin sulfate absorbed into the body is excreted from the kidney and about 50% ~ 90% is excreted from the bile.
In terms of antibacterial spectrum, neomycin sulfate has the best effect on Gram-negative bacteria, especially on Escherichia coli and Salmonella; High dose neomycin sulfate also has a good effect on chicken mycoplasma. However, increasing the dose of drugs will not only significantly reduce the economic value of drugs, but also increase the probability of adverse reactions. Therefore, veterinary clinical treatment for Mycoplasma, in addition to the use of macrolides; In foreign countries, more use of spectinomycin.
However, the combined administration of neomycin sulfate with penicillins, cephalosporins, sardines, fosfomycin, tetracyclines, macrolides and other antibiotics has higher, better and more economical application value for more serious bacterial systemic infection and refractory respiratory diseases, especially when combined with some synergists such as potassium clavulanate, trimethoprim, sulbactam and so on. This is the main reason why we advocate the new use of old drugs.
Therefore, using only one medicine to treat a disease is to follow the chart (use according to the instructions). No one needs any skills and can do it! However, once a drug can not cure the disease, it is wrong to say that a veterinary drug product with guaranteed quality is not good. Because a veterinary drug product with guaranteed quality is only the basis of effective treatment.
How to improve the simple traditional thinking of treating diseases, such as the single use of one drug (excluding illegal compound) and the mechanical addition of two drugs, to understand the pharmacology, clarify the characteristics of the preparation and raise the prescription ability through the summary of technical capabilities and experience such as joint compatibility, synergy and change of usage, that is the real skill and great veterinarian!