Terramycin is a light yellow tablet or sugar-coated tablet, belonging to tetracyclines, easily soluble in water and acidic. It is a broad-spectrum semi-synthetic antibiotic that is antibacterial rather than bactericidal.
Terramycin is a broad-spectrum bacteriostatic agent, and many rickettsia, mycoplasma, chlamydia, spirochetes, amoeba and some plasmodium are sensitive to oxytetracycline. Enterococcus is resistant to it. Others such as Actinomyces, Bacillus anthracis, Listeria monocytogenes, Clostridium, Nocardia, Vibrio, Brucella, Campylobacter, Yersinia, etc. are sensitive to oxytetracycline.
Terramycin has certain antibacterial activity against Neisseria gonorrhoeae and meningococcus, but penicillin-resistant Neisseria gonorrhoeae is also resistant to oxytetracycline. Over the years, due to the wide application of tetracyclines, common clinical pathogens are highly resistant to oxytetracycline, including gram-positive bacteria such as staphylococci and most gram-negative bacilli. There is cross-resistance between different varieties of tetracycline antibiotics.
The mechanism of action of oxytetracycline is that the drug can specifically bind to the A position of the 30S subunit of the bacterial ribosome to inhibit the growth of peptide chains and affect the synthesis of bacterial proteins.
It is used for dysentery, trachoma, conjunctivitis, pneumonia, otitis media, skin purulent infection, etc. It is also used to treat amoebic enteritis and intestinal infections.
The hydrochloride salt of terramycin is light yellow crystalline or amorphous powder, odorless and darkening in sunlight, and is easily damaged in alkaline solutions. It is slightly soluble in ethanol and water, soluble in sodium hydroxide solution and dilute hydrochloric acid.
It can be used to treat respiratory, urethral, skin and soft tissue infections in dogs and cats, including brucellosis, rickettsial disease and chlamydia in dogs, colibacillosis in dogs and cats, and cats caused by rickettsiae The infectious anemia is also used to prevent leptospirosis in dogs.
Oxytetracycline has a broad-spectrum anti-pathogenic microorganism effect, is a fast antibacterial agent, and has a bactericidal effect on certain bacteria at high concentrations. The mechanism of action is that the drug can specifically bind to the A position of the 30S subunit of the ribosome to prevent the connection of aminoacyl-tRNA at this position, thereby inhibiting the growth of peptide chains and affecting the protein synthesis of bacteria or other pathogenic microorganisms.
Oxytetracycline has strong antibacterial activity against Staphylococcus aureus, pneumococcus, Streptococcus pyogenes, Neisseria gonorrhoeae, meningococcus, Escherichia coli, Aerobacter, Shigella, Yersinia, Listeria monocytogenes, etc.; in addition, oxytetracycline also has a strong effect on rickettsia, mycoplasma, chlamydia, actinomycetes, etc.
The oral absorption of oxytetracycline hydrochloride is not complete (about 30%-58% can be absorbed), and the volume of distribution is about 0.9-1.9L/kg. The peak blood concentration after a single oral dose of 1 g is about 3.9 mg/L. The drug is widely distributed after absorption, and can penetrate into pleural effusion and abdominal effusion, and can also enter the fetal blood circulation through the placental barrier, but it is not easy to penetrate the blood-cerebrospinal fluid barrier, so the concentration of the drug in the cerebrospinal fluid is low.
Oxytetracycline can also be distributed in the liver, spleen, bone marrow, bones, dentin and tooth enamel. The drug can also reach high concentrations in milk. The binding rate of oxytetracycline protein is about 20%-35%. The half-life of patients with normal renal function is 6-10h, and prolonged half-life with renal insufficiency.
It can reach 47-66h for anuria patients. The drug is mainly excreted through glomerular filtration, and 70% of the dose can be excreted within 24 hours of administration, and a small amount of the drug is excreted through feces via bile. Hemodialysis can remove 10%-15% of the drug.
A. Oxytetracycline may be used as an alternative treatment for the following diseases:
B. Oxytetracycline can be used to treat tetanus, gas gangrene, yaws, syphilis, gonorrhea and leptospirosis allergic to penicillin antibiotics.
C. Oxytetracycline can also be used to treat respiratory tract, biliary tract, urinary tract and skin and soft tissue infections caused by sensitive bacteria.
D. Oxytetracycline can also be used for acne treatment.
Why was terramycin discontinued? Terramycin, also known as oxytetracycline, is also a derivative with a common polycyclic tetracenecarboxamide core. It belongs to one of the tetracyclines. Because of its low price, many people have used it in the treatment of fish diseases. Now its use in aquaculture is banned.
Although it is a banned drug, it does not mean that it has good effect. Although it is a broad-spectrum antibiotic, it is usually a bacteriostatic antibiotic. It can only kill bacteria when the concentration is high. It has a weaker effect on gram-positive bacteria Staphylococcus, Streptococcus hemolyticus, and Clostridium than penicillins and cephalosporins; it is more sensitive to E. coli, Salmonella, and Pasteurella in Gram-negative bacteria, but it is not as effective as aminoglycosides and chloramphenicol.
Although the antibacterial and bactericidal effect of terramycin is not as good as other antibiotics, its metabolism is slow in the body, and it can also carry out hepato-intestinal circulation like doxycycline. Oxytetracycline is slightly soluble in water and easy to fail in alkaline solutions.
Its hydrochloride salt is commonly used. It has stable properties and is yellow crystalline powder, but it is unstable after being dissolved in water. The absorption of terramycin is irregular and incomplete. It is mainly absorbed in the upper part of the small intestine. When there are polyvalent metal ions such as aluminum, magnesium, calcium, iron, and manganese in the gastrointestinal tract, they can form insoluble chelates with them, thereby reducing the efficacy.
After absorption, it is widely distributed and easily penetrates into the thoracic cavity and abdominal cavity. It is stored in the bile, spleen, teeth and bones in the body. It can be concentrated in the liver and secreted by bile. The drug concentration in bile can reach more than 10 times the drug concentration in the blood. This part of the medicinal effect will be excreted into the intestines along with the bile, be absorbed and utilized again, and enter the hepato-intestinal circulation.
When using terramycin, it should be noted that the dosage range is very large, and the dosage is 5-100 mg per kilogram of body weight. If the dosage is too large, or the oral administration time is too long, it will cause intestinal flora disorder, enteritis and double infection. Especially for renal dysfunction of the body, oxytetracycline is mainly excreted by the kidneys, which will slow down the excretion, prolong the half-life, and increase the toxicity to the liver. Like doxycycline, it is not suitable to be used under alkaline conditions. The effect of taking medicine on an empty stomach is better.
Oxytetracycline has a broad-spectrum antibacterial effect. It also has a certain inhibitory effect on sensitive bacteria including pneumococcus, streptococcus, some staphylococci, Bacillus anthracis, tetanus, Mycoplasma hyopneumoniae, Chlamydia, and spirochetes.
Functions and indications:
On the whole, the antibacterial effect of terramycin is not as good as that of chloramphenicol, cephalosporins, penicillin and aminoglycosides, but terramycin is metabolized slowly and can produce enterohepatic circulation. However, oxytetracycline has many side effects and its excessive use in the aquaculture industry has resulted in terramycin being banned from the aquaculture industry.