Of veterinary chemical therapy medicine basic knowledge of chemical therapy drug definition : where on the invasive pathogen is selectively inhibit or kill, and on the body ( host ) with no or only mild toxicity.

Of veterinary chemical therapy medicine basic knowledge

Chemical treatment

Definition : where on the invasive pathogen is selectively inhibit or kill, and on the body ( host ) with no or only mild toxic effects of chemical substances.

Classification:

Antimicrobial agents: antibiotics and chemical synthetic antibacterial agents

Antifungal drugs

Antiviral drug

Antiparasitic drugs

Anticancer drug

With the disinfectant and preservative difference:

The first section ( antibiotics ) of antibiotics

Antibiotics: formerly known as antibiotics, bacteria, fungi, actinomycetes, microbial metabolites, can kill or inhibit pathogenic microorganisms. Can synthetic or semi-synthetic

Potency by weight or international unit ( IU ) said:

1mg sodium penicillin G = 1 667IU

Penicillin 1mg potassium = 1 559IU

1mg polymyxin B free base = 10 000IU

Other antibiotics for 1mg = 1000IU

Antibacterial spectrum: refers to the drugs that inhibit or kill pathogenic microorganisms, clinical drug foundation.

Resistance: a bacterial sensitivity to drugs decrease or disappearance, cross resistance. Its generation is divided into natural resistance and acquired drug resistance in two.

Antibacterial mechanism

Mainly affect the structure and pathogenic microorganisms interfere the metabolism process:

Inhibition of bacterial cell wall synthesis: on the role of G + bacteria, such as penicillins, cephalosporins, bacitracin and fosfomycin.

To increase the bacterial cytoplasmic membrane permeability: polypeptide, polyene macrolide.

Inhibition of bacterial protein synthesis: aminoglycoside, tetracycline, chloramphenicol, macrolides and forest can amine.

Inhibition of bacterial DNA synthesis: DNA quinolones.

Effects of folic acid synthesis: sulfa drugs, Antibiotic synergist

One, a major role in Gram-positive bacteria drug

1 beta lactam antibiotics:

Penicillins:

Natural penicillin, sterilization and strong, cheap, narrow antimicrobial spectrum, susceptible to acid and beta - acyl inside

Amine mildew damage. Such as penicillin G sodium, potassium; procaine penicillin.

Semi synthetic penicillin, acid-resistant, enzyme and broad spectrum. Such as ampicillin, amoxicillin.

Cephalosporins:

Also called cephalosporins, can be divided into one to four generations, has strong sterilization, broad antibacterial spectrum, allergic reactions in small, stable to acids etc.. As a result of price reason, is mainly used for pets. Veterinary clinically useful Cefradine, ceftiofur etc..

Lactam inhibitors: clavulanic acid ( amoxicillin clavulanic acid ) - 1 : 2-4

Shu TAZ ( sulbactam ampicillin ) - 1 : 2

2 macrolides:

Erythromycin ( Erythromycin ): erythromycin lactobionate ( injection), erythromycin Ethylsuccinate and erythromycin estolate ( acid, oral ), erythromycin thiocyanate ( Veterinary )

Tylosin ( Tylosin ): also known as Thai agricultural, animal special, tartrate and phosphate, the EU started from 2000 to disable as growth promoting agent.

Tilmicosin ( Tilmicosin ): animal special, is characterized in lung tissue and milk drug concentration is high, suitable for livestock pleuropneumonia and mastitis therapy.

Kitasamycin ( Kitasamycin ): also known as kitasamycin, kitasamycin. Is characteristic of most resistant to penicillin and erythromycin of Staphylococcus aureus and effective, can be used for pig VD vibrionic dysentery. Also used as feed additive for pig and chicken.

Spiramycin ( Spiramycin ): mainly used for prevention and treatment of Staphylococcus aureus infection and Mycoplasma disease. The European Union from the beginning of 2000 to disable as growth promoting agent.

Oleandomycin ( Oleandomycin ): mainly used for avian mycoplasmosis, also used as a growth promoting additive.

3 forest can amine

Forest and lincomycin (Lincomycin ): also known as lincomycin oral absorption, incomplete, pig bioavailability is only 20 ~ 50%. For Staphylococcus aureus, Streptococcus pneumoniae, anaerobic bacteria such as Clostridium perfringens infection, mycoplasma, used as a growth promoting additive. With spectinomycin combined consisting of Lee High dx.

Clindamycin ( Clindymycin ): oral absorption than forest lincomycin, antimicrobial effect than the forest can be in 4 ~ 8 times.

4 polypeptide

Bacitracin ( Bacitracin ): taken orally with little absorption, mostly in 2 days with fecal discharge. On renal toxicity, should not be used for systemic infection. The European Union from the beginning of 2000 to disable as growth promoting agent.

Polymyxin B ( Polymycin B ): narrow spectrum, mainly used for negative bacillus infection, but due to renal toxicity and nervous system toxicity, more topical use.

Colistin ( polymyxin E: Colistin ), oral absorption, for the treatment of livestock and poultry Escherichia coli diarrhea and dysentery.

5 other antibiotics

Tiamulin ( Tiamulin ): also known as Tai Miao Ling Zhi Yuan, net. Good oral absorption, drug distribution in vivo of extensive, mainly used for respiratory tract diseases of livestock and poultry and swine Treponema dysentery.

In two, a major role in Gram-negative bacteria drug

1 aminoglycoside

Streptomycin ( Streptomycin ):

Gentamycin sulfate ( Gentamycin ):

Kanamycin ( Kanamycin ):

Amikacin ( Kanamycin ): amikacin

Neomycin ( Neomycin ):

Spectinomycin ( Spectinomycin ):

Apramycin ( Apramycin ):

Common features: 1 sulfate, easily soluble in water, stability;

2 oral absorption, as intestinal infection drug;

3 pairs of Gram-negative bacteria and Staphylococcus aureus sensitive, ineffective against anaerobic bacteria;

4 damage to cranial nerve, kidney toxicity.

Three, broad-spectrum antibacterial drugs

1 tetracyclines

Natural products:

Oxytetracycline ( Oxytetracycline ): also known as oxygen tetracycline

Tetracycline ( Tetracycline ):

Chlortetracycline ( Chlortetracycline ):

Semi-synthetic:

Doxycycline ( Doxycycline ): also known as doxycycline, doxycycline

Features.

1 pairs of Gram-positive bacteria, gram-negative, spiral, Rickettsia, chlamydia, mycoplasma, protozoa ( ball), inhibit.

2 antibacterial activity for doxycycline tetracycline chlortetracycline and oxytetracycline > > >.

3 in the gastrointestinal tract, calcium magnesium, aluminum, iron, zinc and other polyvalent ions and drugs chelate formation, the impact of drug absorption.

2 chloromycetin

Chloramphenicol ( Chloramphenicol ): disable, inhibition of bone marrow hematopoietic function, performance for the reversible pancytopenia and irreversible aplastic anemia.

Thiamphenicol ( Thiamphenicol ): also known as thiamphenicol, thienamycin; do not produce aplastic anemia, but mild inhibition of blood cell production.

Florfenicol ( Florfenicol ): also known as florfenicol, animal special, without the toxicity, embryo toxicity but has disabled, pregnant animals. On porcine Actinobacillus minimal inhibitory concentration for 0.2 ~ 1.56 u g / mL.

Second section of chemical synthetic antibacterial agents

1 sulfonamide and its synergist

Intestinal absorption of sulfonamides:

Sulfanilamide ( SN )

Sulfadiazine ( SD )

Sulfamethazine ( SM2 )

Sulfamethoxazole pyrimidine ( SMZ ): SMZ

SDM ( SMD ): sulfonamide - 5 - SDM, anti-inflammatory sulfonamide

Sulfamonomethoxine ( SMM ): sulfonamide - 6 - SDM, sulfamonomethoxine

Sulfa - 2, 6 - Erjiayangmiding ( SDM )

Sulfa - 5, 6 - Erjiayangmiding ( SDM ' ): week acting sulfonamide

Sulfaquinoxaline ( SQ )

Sulfaclozine

Intestinal difficult absorption sulfonamides:

Sulphaguanidine ( SM, SG )

Topical sulfonamide:

Silver sulfadiazine ( SD-Ag )

Antibiotic synergist:

Trimethoprim ( TMP ): trimethoprim

Two trimethoprim ( DVD ): two trimethoprim, enemy net, special for animal

Sulfa drugs:

1 broad-spectrum slow action bacteriostatic drugs, antimicrobial effect of intensity of the order: SMM > SMZ > SD > SDM > SMD > SM2 > SDM > SN '

2: bacterial resistance and easy to produce drug resistance, the sulfa drugs have cross-resistance with other antibacterial drugs, but no cross resistance.

3: toxic side effect for chronic poisoning, the injury to the urinary system ( crystallization of urine, hematuria ), digestive disorders ( multiple enteritis ), juvenile animal immune system suppression, egg drop and breakage, soft shell increases.

4: attention to dose and duration of use principle, sufficient water to increase the amount of urine, preferably with a sodium bicarbonate with clothes for alkalinization of urine, laying hens to disable, selection of high efficacy, solubility and acetylated low rates of sulfa drugs, such as SMM, SMD.

5 autosomal and synergist to

5: 1 proportion.

2 of the quinolone

In 1962 the first clinical applications of the first generation is nalidixic acid ( Nalidixic Acid );

Representative of the second generation drugs for 1974 Pipemidic Acid ( Pipemidic

Acid ) and animal special flumequine ( Flumequine );

In 1978 third the first synthetic generation for norfloxacin ( Norfloxacin ), then 20 years a large number of fluoroquinolones in use.

The following characteristics:

1 broad antibacterial spectrum:

2 strong sterilization: bactericidal concentration is 0.1-10 / g / mL;

3 fast absorption, distribution in vivo: treatment of the various systems and tissue infection;

4: inhibition of antibacterial effect of unique DNA gyrase, interference DNA replication allows bacteria to death;

5

Small toxic side effect : the young animals ( dogs, horses ) and pregnant domestic animal disable, have adverse effects on growth of cartilage.

China's ratification in veterinary clinical application with:

Norfloxacin ( Norfloxacin ): Norfloxacin

Pefloxacin ( Pefloxacin ): perfloxacin

Ofloxacin ( Ofloxacin ): ofloxacin

( Ciprofloxacin ): Ciprofloxacin CPFX

Lomefloxacin hydrochloride ( Lomefloxacin ):

Enrofloxacin ( Enrofloxacin ): ethyl ciprofloxacin

Danofloxacin ( Danofloxacin ): danofloxacin

Two fluorine ( Difloxacin ): difloxacin

Sarafloxacin ( Sarafloxacin ):

The above four kinds of animal of special. Overseas listed animals: special medicine and marbofloxacin ( Marbofloxacin ) and Orbifloxacin ( Orbifloxacin ) etc..

3 quinoxaline type

Carbadox ( Carbadox ): carbadox, original growth promoting agent, because have mutagenic effects, many countries now ban.

Acetyl flumequine ( Maquindox ): also known as mequindox, domestic synthesis, broad-spectrum antibacterial effect, for the treatment of swine dysentery drug of choice, on piglet yellow scours,, avian Escherichia coli disease effect well. Cannot be used as growth promoter, has a certain toxicity (long-term use or 3-5 times therapeutic amount ), poultry, especially sensitive.

V olaquindox (Olaquindox): used as antibacterial and growth promoting agents, with the promotion of anabolic effect, improve the feed conversion rate and weight gain, the other against pasteurellosis, Escherichia coli has inhibitory effect can be used for the treatment of fowl cholera, and piglet diarrhea and other intestinal infections. Chicken, duck, sensitive to the chemicals. Due to the withdrawal period ( 35 days), can only be used for growing pigs ( less than 35kg ), disable in poultry ( Chinese Veterinary Pharmacopoeia, 2000).

4 nitro furan

Cefuroxime what Triadimefon ( Furaltadon ): also known as furaltadone, with carcinogenic effects, have been banned.

Furacilin ( Furacillin ) : this type of poisoning, as a disinfectant for external use.

Nitrofurantoin ( Nitrofurantion ): also known as nitrofurantoin, toxicity, disabled.

Furazolidone ( Furazolidon ): also known as furazolidone, use more, now disabled.

This class of drug toxicity, chicks and piglets are particularly sensitive, and because of the carcinogenic and mutagenic effects, has banned as feed additives.

5 nitro imidazole

Metronidazole ( Metronidazole ): also known as metronidazole, metronidazole imidazole, for the majority of obligate anaerobic bacteria with stronger effects such as Clostridium perfringens, on aerobic bacteria is invalid, and resistant trichomonas and Amoeba effect. The cells have a mutagenic effect, is prohibited for pregnant domestic animal.

M ornidazole (Dimetridazole ): also known as the two metronidazole, two metronidazole imidazole. With a broad spectrum of antibacterial and antiprotozoal activity, for the treatment of swine dysentery and chicken histomoniasis. Chicken of the goods is sensitive.

Section third antibacterial drugs combined application

1 beta lactam:

With clavulanic acid ( clavulanic acid ), Shu TAZ, tazobactam ( tazobactan ) combined with a better enzyme inhibition and synergistic effect of protection.