Compatibility of drugs

Compatibility of drugs
The incompatibility of drugs is the adverse changes in the use of different drugs in the same prescription. There are 3 kinds of compatibility, that is, the efficacy of the combination of taboo, the physical compatibility of the taboo, the chemical compatibility of the taboo. Physical compatibility is the physical changes that occur between drugs such as adsorption, and the effect of drugs, chemical compatibility, chemical reaction, the combination of different drugs, chemical reaction, and ultimately affect the efficacy or increase the toxicity of drugs.
The phenomenon of drug compatibility is very common, so should pay special attention to, many drugs should be used alone for good. For example: at the same time, Trichlorfon and quicklime can produce poison
More dichlorvos; mixed acidic drugs and basic drugs using possible chemical reactions, the drug failure I of ferrous sulfate can decrease the bactericidal effect of chlorine disinfectant; zeolite and activated carbon has a strong adsorption effect, other drugs should be avoided and their mixed use; the drug tetracycline and not containing iron, calcium, magnesium, aluminum, or feed the same service, because of its complex formation is not easy to absorb the impact absorption, it is not the same service for the latter with sodium bicarbonate, the increase of pH value, can reduce the solubility and affect the absorption of amino sugar; glycosides and cephalosporins combined, can cause acute renal tubule multi point necrosis; cephalosporins and amino sugar glycosides, cephalosporins combination, can increase the renal tubular toxicity.
Dose of antibiotics
Initial antibiotic or antibiotics due to the impure product, not by weight to measure antibiotic intensity, so stipulated that the titer. This particular “unit” is a kind of effective antibiotic composition of the scale. When an antibiotic is made into a pure chemical substance, it can be expressed as a unit of weight. For example, 1 mg penicillin sodium containing 1667 units, or say 1 unit O. 6 micrograms. 1 mg streptomycin alkali containing I OOo unit, namely 1 unit = 1 micrograms; oxytetracycline, erythromycin, kanamycin, neomycin are to its free base 1 mg set for 1 000 units; tetracycline and chlortetracycline element in its hydrochloride salt I mg as 1 000 units I Yi bacteria B to its free base 1 mg set 10 OOo unit (i.e. 1 withdrawal g quite to the 10 units); and business nystatin per 1 mg for 3 been 7oo units.
As mentioned above, the doses of antibiotics is generally to potency unit and a unit of weight not weighing) to represent, for example, oxytetracycline 250 000 units equivalent to 250 mg oxytetracycline soda. Here the 250 mg not weighing, but to a unit of weight. The relationship is
Weight = total number per unit of antibiotic
For example, packaging of oxytetracycline hydrochloride, per capsule containing 250 mg (rather than that of oxytetracycline 250 000 units), such as the purity of the product is 880 units Lu mg, capsulizing actual weighing is computed according to the formula for 294 mg.
Can be seen that the dose of antibiotics have a certain complexity, in the use of the process must be noted.

Antibacterial spectrum of antibacterial drugs

Antibacterial spectrum of antibacterial drugs
Antimicrobial spectrum is the range of varieties of bacteria that are sensitive to the drug. Due to the diversity of its physical and chemical properties, the mechanism of its effect on the bacteria is also different. Some are interfering with bacterial cell wall synthesis, some of the damage of bacterial cell membrane, some of which affect the synthesis of bacterial cell proteins or nucleic acids, which lead to drug sensitive bacteria in the range of different drug. So different drugs have different antibacterial spectrum, some drugs are mainly gram positive bacteria (according to Gram stain reaction, can be divided into gram positive bacteria and gram negative bacteria) sensitive, some drugs are sensitive to gram negative bacteria, but also some of the drug gram positive bacteria and gram negative bacteria are sensitive. The two class is called as antibacterial agents, which is referred to as a broad-spectrum antibiotic. The range of different drugs among different drugs is different. The gram negative bacteria were more sensitive to the drug than gram positive bacteria. Fish pathogenic bacteria is gram negative bacteria, so the use of antibiotics in aquaculture is the majority of broad-spectrum antibacterial drugs.
Drug residues and drug withdrawal period
After drugs into the body, to experience from the absorption, distribution, metabolism, and so on a series of processes, and finally discharged from the body. These processes are in need of a certain period of time, and the length of time is mainly related to the physical and chemical properties of drugs and the variety of animals. The drug is completely eliminated from the fish, some only a few days, while others demand for several months. The residual amount is the content of the drug in the body of the fish market. The content may be very low, but when the human body long-term intake of residual drug, the drug is likely to accumulate in the human body, and then the human body to produce toxic and promote the human body to produce drug resistance. To this end, many countries have used the drug for the approval of the withdrawal period. That is to say, if the use of a certain kind of medicine, the need to stop the medicine for a period of time after the sale, so that the fish in the amount of drug residues to reach the maximum allowable concentration of the following. China has this kind of rules (the people’s Republic of China Ministry of agriculture Announcement No. 235), especially the aquatic products export enterprises in this regard problems must be paid attention to, otherwise it will seriously affect the export of aquatic products, the problems in the export of Japanese eel (Anguilla japonica) had precedent. Even more important is the residue of the drug will seriously affect the health of the vast number of consumers in Ankang.

Prevention and treatment effect and adverse reactions

Prevention and treatment effect and adverse reactions
Drugs for the prevention and treatment of diseases, can produce a beneficial effect on the body, but also produce some adverse reactions to the body. Preventive action can be divided into preventive effect and therapeutic effect. In terms of treatment can be divided into symptomatic treatment and due to treatment, which is temporary and permanent. The former is to reduce or eliminate the symptoms of the disease, the latter is to eliminate the cause of the disease, because the treatment can eliminate the cause of the disease to achieve the effect of a cure, symptomatic treatment can not eliminate the cause, but can relieve symptoms. In clinical practice, should follow the “acute is the treatment of its standard, light is the treatment of its own, the specimen and treatment. Principle.
There are two main types of adverse reactions, that is, side effects and toxic reactions. The former refers to the role of the drug in the treatment of dose not related to the role of the role, generally relatively mild. Such as the drug in the body after the acetylation of acetyl. The lower solubility of sulfacetamide, in urine is acidic easy in renal tubular precipitation and damage the kidneys, this is sulfa drug side effects. Toxicity is usually in the use of large doses, the course is too long or the individual to a higher sensitivity of drug. In order to avoid the occurrence of toxicity, pay attention to do not any more than the drug commonly prescribed amount, in addition to the side effects and toxicity, adverse reaction and allergic reaction, allergy and idiosyncratic reaction, but for fish this several adverse reactions of little significance.
Drug resistance
Although many effective treatment of antimicrobial agents against bacterial diseases in fish, but bacterial disease but throughout the year in place. This is the case, the reason, if the method is correct, but also not the drug has failed, it is the reason for the inhibition of the role of drugs to reduce the pathogenic bacteria. Once effective drugs become inefficient or invalid, it is because pathogens to drugs cause resistance of, called the nature of bacteria resistant Xiaohan, but does not have the properties of common bacteria known as drug sensitive bacteria. Bacterial resistance to antimicrobial susceptibility is reduced. The emergence of drug resistant bacteria is the result of drug selection, which is due to the use of antibacterial drugs. To make the sensitive bacteria inhibited or killed, the original account for a very small number of anti drug strains to the opportunity to multiply into a dominant group, the disease caused by these bacteria is difficult to use conventional drugs to control. However, bacteria are resistant to a particular drug, which may be sensitive to the other, but at times the bacteria are resistant to one drug, and it may become resistant to another, called cross resistance. There are cross resistance in general drug. If, for example, a bacteria resistant to tetracycline, then of oxytetracycline will appear cross resistance, bacteria on a sulfa drug resistance, then to another sulfa drugs certainly with drug resistance. Therefore, in order to make the correct choice of antibiotics, we must carry out the pathogen isolation, and then carry out the drug sensitivity test of pathogenic bacteria, in order to determine the selection of drugs for treatment.
If a drug has been used widely, it will appear to be resistant to the drug. The problem of drug resistance bacteria is not only the problem of drug efficacy, but also can spread the drug resistance to human pathogenic bacteria, which makes the treatment of bacterial diseases difficult to be directly or indirectly. Therefore, the use of antimicrobial drugs in public health has received great attention. In turn, human and animal drug resistant bacteria can also pass through the feces, through various channels to enter the pond, and the drug resistance to the fish bacteria, causing the emergence of drug resistance of pathogenic bacteria, which should also cause people’s attention.
In order to prevent resistance, need to pay attention to the following aspects, that for the first time large dose principle, rotation use different drugs, with medication, long enough for a course of treatment and the use of a new generation of antibacterial drugs such as norfloxacin.

Several important concepts

Several important concepts
1, drug formulation and preparation
Dosage form is a kind of form that can be processed and modulated, easy to use, save and transport. The dosage form can be divided into liquid, gas, solid, semi solid. Preparation is an individual dosage form of a drug.
2 local effect and absorption
The function of the drug is divided into local and absorptive function. The former is the drug to be absorbed into the blood before the play the role of, such as topical disinfectant on the surface of bacteria killing effect and dipterex of Lernaea ‘”absorption refers to the drug is absorbed into the blood after the play the role of, such as chloramphenicol for furuncle hysteria and ulcer disease. The role of the absorption is extensive, which can be involved in all parts of the body. However, due to the different physical and chemical properties, the distribution of them is not the same as in vivo residence time (or in vivo process). For example, after oral absorption, the part of the body is damaged, and the rest are excreted in the urine, and the drug concentration in urine can be used for sensitive storage. Therefore, different drugs have different indications and effects, should be understood in detail.
3 direct and indirect effects
The direct effect is that the function or form of the function of the object is changed. The indirect effect is the secondary function of the body fluid regulation. The bactericidal or antibacterial effect of the antibacterial drugs is the direct action of the drugs in the aquatic drugs play an indirect role in the drug less.
4 synergistic and antagonistic effects
When two or more drugs used in combination, the role can be strengthened due to compensate each other, can be cancelled or reduced, the former synergistic effect, which is called the twist resistance and dispensing can be using the synergistic effects of other drugs, to strengthen the main drug therapy, and should pay attention to avoid the role of anti Chu. But sometimes in order to offset the side by using bamboo Weiyao other drugs Hangzhou antagonistic effect
With the further study of the mechanism of drug action, the antibacterial drugs can be divided into four categories: 1. 2, stationary or slow acting bactericidal agent, streptomycin, card the kanamycin, gentamicin, 3, fast efficient antibacterial agent, chloramphenicol, erythromycin, tetracycline. 4, slow acting agent — sulfa drugs.
This classification has certain directive significance to the application of antibacterial drugs. The combination of the first and the second drugs can produce a synergistic effect, which is due to the destruction of the integrity of the cell wall, and the second type of drug is readily available in the cell. The third drugs can quickly block the synthesis of proteins, so that the bacteria are still in a state of rest, and therefore, when the first type of combination of the latter may lead to the weakening of the latter activity. Third types and second kinds of combination, often can get the cumulative or synergistic effect, generally does not have an antagonistic phenomenon. While the third category of the first class of antibacterial activity without significant influence, and sometimes can produce cumulative effect, similar drugs can also be used in combination.
With the small amount of disinfectant solution containing chlorine or bromine, iodine can greatly enhance the bactericidal ability. There are some substances have synergistic effect on chlorine containing disinfectant.


For the pathogen, prevention and control measures are mainly to prevent the introduction of pathogens and the use of drugs to kill pathogens in the water body. Pathogens into people farms all of the following several ways fish seedlings, broodstock with pathogen and feed are contaminated with the pathogen and transportation tools with pathogens, headwater streams human pathogens, the birds with human pathogens. As the source of infection, disease of fish, fish is the most dangerous, farmers must be properly disposed of. Lurk in pond sediment of a large number of pathogens, especially bacteria and parasite eggs, which is advocated clear pond is one of the reasons. Fish pathogens are mostly in the condition of pathogenic bacteria, the most common pathogenic bacteria in our country. That is to say, this kind of bacteria is common in the water body, but only when the fish body’s resistance drops to cause the disease. Water is also a condition of the disease, only when the body has trauma or infection can be infected with the bacteria, otherwise it will not be infected with the water. But some pathogens is contagious, they enter the incidence of aquaculture water up to a certain number can lead to diseases. These pathogens including infectious pancreatic necrosis virus, infectious hematopoietic necrosis virus, sticky Cryptosporidium, Ichthyophthirius etc.. At present, antimicrobial drug use is still the main means of pathogen control, however, in addition to drugs and other measures can used to kill pathogens, has been adopted in the production of this type of technology, mainly useful ultraviolet lamp of pond water were irradiated to kill some pathogenic bacteria, photosynthetic bacteria, Bdellovibrio and biological prevention technology.
It is important to control and adjust the water quality. The deterioration of water quality and water quality is a very important and common factor affecting the resistance of fish. In the production process, the changes of dissolved oxygen, ammonia nitrogen, nitrite nitrogen, nitrite nitrogen, pH value, water temperature and salinity in sea water, etc.. In addition, the increase in the content of organic matter in the water body will be conducive to the breeding and propagation of pathogens. To control water quality must be to strengthen the daily management of aquaculture, can through the pond dredging, stocking density, moderate feeding control and change the water regularly and other measures to regulate water quality. Although there are reports that the environmental improvement agent has a certain effect on the water quality, but the use is not practical in production. In this regard, ecological control technology has great potential, the more successful examples of photosynthetic bacteria and gracilaria.
Drugs in the prevention of fish diseases in the process of role is only to control pathogens on the link, and in the fish body resistance to disease and the improvement of environment regulation role is very limited. However, fish once the disease, then only rely mainly on drugs, if the whole process of breeding from the above 3 aspects to consider, reduce the occurrence of disease, can choose to measure more, and once the disease, it can only rely on drugs.

The status of drugs in the prevention and treatment of fish diseases.

The status of drugs in the prevention and treatment of fish diseases.
At present, the prevention and cure of disease in farmed fish, the agriculture, fisheries and conservation is the main use a variety of drugs, and some even completely dependent on drugs and fish not sick with drug prevention, sick with drug therapy, and often use multiple drugs at the same time or take turns, for other control measures is rarely considered. However, it should be known that in the pond a large number of drugs used in the presence of many ills, such as pollution of the environment, the poison of the drug to the fish, the residues of drugs in the fish body and the drug resistance of the pathogen, etc.. Actually, the prevention and treatment of fish diseases in addition to drugs, there are a variety of methods can comprehensive use, totally dependent on drugs can not solve the problem of. Therefore, the most important for breeders is to improve the breeding technology, strengthen the management, the use of comprehensive measures to reduce the occurrence of the disease, thereby reducing the use of drugs, do. No disease prevention, early treatment, prevention and treatment.
Infectious diseases of fish are the result of interaction between pathogen, fish and environment. Following from these aspects analysis the causes of disease, and introduces the main methods and Countermeasures for the prevention and treatment of fish diseases.
1 fish body
The occurrence of the disease must also have two conditions, namely, susceptibility and resistance to decline. That is to say, only when the water body of the fish can be infected with the pathogen, while the fish’s resistance to disease and decline, it is possible to attack. Susceptibility is mainly related to fish species, age and so on. For example, silver carp, bream fish not infected grass carp hemorrhage of reovirus from, grass carp, although can be infected with the virus, but Ctenopharyngodon idella this virus is not easy. Therefore, in the process of disease prevention and control of this link, the following measures can be used.
New varieties of fish (1) breeding for disease resistance and strong fish a fish disease resistant force and strength of this kind of pathogen sensitivity is determined by genetic factors. Therefore, we can fish species breeding natural immunity, can also use molecular biology technology breeding disease resistant force is powerful, many of our scientific research units are engaged in the research, at present focus in grass carp. This is because the grass carp is a kind of high quality fish in China. It grows fast and has a low cost, but the disease is the most of the fish. As a breeding unit, we should pay attention to the information, timely introduction of resistance to strong fish, in order to improve the breeding efficiency. Moreover, it is necessary to recognize that the new breed of disease that has already been developed or cultivated in the future is just a resistance to some disease, but it is not possible to resist all diseases. But we still can according to the different breeding fish to certain diseases have different resistance this principle to guide preventive culture, for example, can the harmonious culture of grass carp, bighead carp, crucian carp, carp and other to reduce or avoid the occurrence of hemorrhagic disease of grass carp, reduce the silver carp and big head carp outbreaks of fish diseases.
(2) artificial immune system is a very hot research field at home and abroad, the main use of active immunization, active immunization with inactivated vaccine and attenuated vaccine, in foreign countries have been commercialized fish vaccine. The use of vaccines can be targeted to improve the resistance of the body to a certain or some of the pathogen. For example, through the injection of Grass Carp hemorrhage tissue vaccine can prevent the occurrence of pulp, Grass Carp hemorrhage. This technology has been widely used in China, but due to the lack of a simple and effective way of immunization, which makes the practical use of immune disease prevention technology has been greatly affected. This is because the use of injection method, time consuming, and the damage to fish. In addition, the immune effect of the vaccine is affected by many factors, such as the production process, the use of concentration or dose, the immune pathway and the procedure. Even if it can achieve the desired effect, but because of the specificity of the vaccine is too strong, it can only prevent one or several (for many vaccines) disease, not to prevent the occurrence of other diseases.
(immune enhancement agent used in the feed to add polysaccharide or some Chinese herbal medicine, long-term feeding can improve the fish specific immune and non-specific immune function, so as to enhance the resistance to disease. At present, the domestic and foreign markets have fish with immune enhancement agent supply.
(4) using reasonable feed is one of the most basic means to improve the resistance of fish. Breeding fish if long-term malnutrition, or lack of certain vitamins or trace elements, will seriously affect the fish’s disease resistance, which can induce the occurrence of disease.
In addition, the stress response of fish should be avoided in the process of breeding, because the stress response of long time can result in the decrease of the resistance to the fish, and increase the susceptibility to various pathogens.

The study of enteritis vaccine

The study of enteritis vaccine
R. to (1962) has on the grass, black carp infectious enteritis disease for vaccine research, reported the artificial immunity method in laboratory injection, warm, cast in the pond feeding enteritis vaccine trials, and effects of environmental factors on vaccine and immune fish and control fish serum protein composition were determined. In experimental rabbit immune and pathogens of enteritis (punctata gas single cell bacteria) of preparation of vaccine, the rabbits in vivo stimulates the production of agglutinating antibody titer reached 1:5 160 grass carp mouth to feed and immunological test, rubber catheter for the vaccine was poured into the intestine and its concentration, with 100 million bacteria per milliliter, immune interval for 5 days, a total of three times, third feeding mouth vaccine after 7 days, attack tests. After feeding mouth vaccine, fish produced certain protective immunity in mice.
The pond fed immunity test, per kg body weight of fish fed 1 ml vaccine (25000000000 bacteria / ml), were fed 4 times. Although four pond to the end of December were not found in the diseased fish, but from the point of view of the fish in the moat attack test, after immune shows higher resistance. The three batch of fish, the first two batches of fish, the incidence of fish, although the number is equal to the control fish, but the time of death is later; the fish, the third batch of immune test, in addition to the onset time is relatively late, and the incidence of less than 20%, while the control group was as high as 80%.
Immune test of the gill disease of grass carp
Weihu harm inactivated vaccine and inactivated inactivated) in (and Ji Guoliang Chen Changfu 1988 of prepared three different fish harm Myxococcus Miao Miao formalin inactivated vaccine (adding 1% formalin, 28 DEG C for 24 hours, referred to as F-MP and phenol added 2% phenol, 28 degrees C for 24 hours (P-MP) and heat inactivated vaccine (bacteria liquid under 60 DEG C water bath inactivated 1 hour, referred to as H-MP) tested grass carp to 3 kinds of different fish Myxococcus vaccine immune response, the vaccine were diluted into a bacteria / mL concentration per tail muscle injection of 0.2 ml of immune fish. After immunization, the titer of serum antibody titer of the grass carp was 256 ~ 4 F-MP, 256 ~ 2 096H-MP, 128 ~ 1024, respectively. They were in the 21 to 28 days after the injection to reach the peak, 28 days after a gentle or slightly decreased. While the control group except for the individual antibody titer reached 8, the rest are in about 4. The mortality rates of F-MP.H-MP and P-Mp in the immunized group were 10%.16.7% and 5%, respectively, while the control group was 60%, which showed that the fish had a certain protective force.
In oral fish harm the viscosity of the bacterial lawn immunity test, in addition to the species of Lu vaccine, and fish harm sticky aureus ester polysaccharide (LPS), concentration of 3 kinds of vaccine were 109 bacteria / ml concentrations of LPS for 2 mg / ml, respectively according to the amount of per 100 tail fish every day 1 ml vaccine, mixed with bait in the early, late twice feeding. Attack test was carried out for 3 times, the first time in a row for 7 days, second times for 14 days, 21 times for third days. The results showed that the difference was not significant between the 1 consecutive days of attack and mortality. The 21 division was slow in death. The protective force was the beginning of feeding for 14 days.