Amoxicillin, the most widely used antibiotic in pig farming?


Before talking about the clinical pharmacology of amoxicillin, let us review its theoretical pharmacology. Amoxicillin is white or off-white, slightly soluble in water, acidic in aqueous solution, and a broad-spectrum antibiotic of the β – lactam class. Does it sound a bit long? I’m a little out of breath! No way, this is the foundation, without it, we directly talk about the pharmacology of clinical treatment, some comrades will have obstacles in understanding.


In terms of clinical treatment and pharmacology, this passage is shown as follows: as a penicillin antibiotic, amoxicillin is easily affected by many factors such as temperature, humidity, light, electrolytes, trace elements and vitamins, and chemical reactions such as hydrolysis, cracking, and oxidation occur. Changes lead to lower efficiency; although our grassroots are not equipped with professional testing equipment, the inherent instability and changes of things are usually manifested on the outside.


For example, the characters change from white, off-white to yellow, brown, hard lumps, and a lot of spots of different shades, etc. In clinical treatment, once such amoxicillin soluble powder is found, do not use it, it is not only ineffective, Moreover, sometimes it will bring more serious side effects.


Since amoxicillin is slightly soluble in water, the aqueous solution is acidic and has stability problems. If the water solubility of the amoxicillin soluble powder preparation is not good, it will make the drugs that enter the digestive tract orally mixed with food, and it is difficult to dissolve and be absorbed by the body.


Although the original drug solution of amoxicillin is acidic, it has poor stability in acidic aqueous solution; then, what about the alkalinity? The Amoxicillin Soluble Powder “Palaxin” of Intervey is neutral to weakly alkaline, and the Amoxicillin Soluble Powder of Vic, France is weakly alkaline, but it is too alkaline to it is good!


There are so many factors that affect the stability of  amoxicillin soluble powder. When doing formulation development and production, in order to improve its stability, water solubility and adjust its appropriate pH value, it is impossible for manufacturers to just “amoxicillin + excipients”, right? However, have you noticed that this is a contradiction? And the solution of these problems and contradictions is directly related to the curative effect of amoxicillin soluble powder. This requires the R&D and manufacturer of amoxicillin soluble powder to make great efforts in R&D and production to produce good products!


Therefore, don’t think that amoxicillin soluble powder: as long as it meets the national standards and passes the inspection according to the national standards, the products of that manufacturer are the same! So, under the same qualified conditions, come on: compare prices! Who’s cheaper, who’s I’ll use! This concept of medication is wrong! Not to mention that you are tested according to Chinese national standards, but you are qualified by the US and EU standards, which cannot directly prove that the clinical treatment effect is good!


Because those are all relying on various testing instruments and various physical and chemical indicators and data. Not for pigs or chickens, but for the government and everyone here, and more for manufacturers to use for publicity. To really useful data, it comes from the clinic, from everyone’s practice and personal experience. It comes from the fact that you have used it, she has used it, and then you share it with us and say: for whom? when? how to use? How good!


Let’s review another theoretical pharmacology of amoxicillin: amoxicillin produces a strong broad-spectrum bactericidal effect by acting on the cell wall of bacteria, and has a strong broad-spectrum bactericidal effect on most Gram-positive bacteria such as Streptococcus, Staphylococcus, Clostridium welchii It is sensitive to gram-negative bacteria such as Escherichia coli, Haemophilus parasuis, Salmonella, Proteus and Pasteurella, etc. It has good oral absorption and high blood concentration, so it has a better therapeutic effect on systemic infections. ; Monogastric animals (such as pigs, chickens) have absorption rates ranging from 74% to 92% after oral administration , and the contents of the gastrointestinal tract affect the absorption rate.


Some of these words should not be taken seriously, because they are ineffective; some should be taken seriously, but they need to be clinicalized, otherwise, they will not be effective. This is why I have always emphasized: theoretical pharmacology is the foundation, not practical; it needs to be transformed into clinical treatment pharmacology in practice! Then, the above theoretical pharmacology is mainly manifested in clinical treatment pharmacology: Amoxicillin acts on bacterial cell walls to sterilize, making it compatible with aminoglycoside drugs, polypeptide drugs, etc., which is synergistic antibacterial, which is very important for the prescription of effective treatment. Is it useful?


Amoxicillin is a concentration-dependent fungicide, and the food in the gastrointestinal tract of animals will affect its absorption rate. Therefore, clinical administration requires controlled feeding and centralized administration, and the therapeutic effect will be good. Although the theoretical pharmacology says that it can be effective on most Gram-positive bacteria and Gram-negative bacteria, it has objective drug resistance in some areas, as well as the cell wall thickness of positive bacteria and the thin cell wall of negative bacteria.


Therefore, in the clinical treatment of veterinary medicine, amoxicillin is actually mainly used for the treatment of systemic infections and infections of the respiratory tract, intestinal tract and urinary system caused by Streptococcus, Haemophilus parasuis and Clostridium welchii in pigs. In poultry, amoxicillin is mainly used for the treatment of Escherichia coli, Salmonella, Clostridium welchii, Pasteurella and some respiratory and intestinal gram-positive bacterial infections.


Finally, let’s review the last theoretical pharmacology of amoxicillin: chicken mixed drink, 60mg amoxicillin per 1L of water ; if it is calculated in kilograms of body weight, chicken orally take 20-30mg amoxicillin per Kg of body weight , use 3-5 times in a row days, chicken withdrawal period 7 days, and so on. The clinical treatment pharmacology is: for pigs and chickens, 60 mg of amoxicillin per 1 L of water is administered as a mixed drink, which is 100% ineffective for the treatment of systemic infection; for the treatment of systemic infection, it needs to be reduced according to the upper limit of 30 mg/Kg of body weight. Calculation of the dose, there is a certain therapeutic effect.


Why is it called a certain therapeutic effect?


That’s because this dose is very effective in areas sensitive to amoxicillin. What? Someone said to do a drug susceptibility test? Don’t be superstitious, let alone believe it all, it can only be used for reference; because amoxicillin can’t be tested for gram-negative bacteria in vitro, most of which can’t be done. Some are resistant, some are not resistant at all, but you just can’t do it. There is a reason for this. This time, we are not talking about the in vitro susceptibility test of drugs, so we will not talk deeply and delay the topic!


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