What Are the Different Tetracycline Antibiotics?

Tetracyclines are a class of broad-spectrum antibiotics produced by actinomycetes. The structure of erythromycin, dimethylaminotetracycline, and the like all contain a tetraphenyl original skeleton.

Chlortetracycline

Oxytetracycline

Dimecycline

Doxycycline

Methoxycin

Minocycline

tetracycline

Tigecycline

Lysine tetracycline

Tetrahydrocycline

Metocycline

Chinese name: Tetracycline antibiotics
Foreign name: Tetracyclines
Nature: Broad-spectrum antibiotics

To source: Actinomycetes production
Including: Chlortetracycline
Effect: For the diagnosis of malignant tumors

Introduction to Tetracycline Antibiotics

Widely used in a variety of bacteria and rickettsial, chlamydia, mycoplasma and other infections, its adverse reactions are: gastrointestinal reactions. liver damage. kidney damage. Affects the development of teeth and bones, so children under 8 years are prohibited. There is local irritation, so intramuscular injection is not allowed, and the intravenous drip should be fully diluted. Have allergic reactions. The use time is slightly longer, which may cause intestinal flora imbalance. Medicines and foods containing calcium and more than two valence metal ions can form complexes and hinder their use.

Tetracycline antibiotics Tetracycline is a bacteriostatic broad-spectrum antibiotic. It has effects on rickettsial bodies, chlamydia, mycoplasma, and spirochaetes in addition to gram-positive and negative bacteria. Adults can take it orally. When intravenously, it is diluted with glucose solution and then instilled. Note: Hydrochloride is better absorbed than alkali when taken orally, but it is more irritating. It should be taken on an empty stomach to avoid interaction with food. It is strictly forbidden to use after expiration. Use with caution in patients with liver and kidney dysfunction. The following children are disabled. A large class of semi-synthetic broad-spectrum antibiotics that have bacteriostatic effects and bactericidal effects at very high concentrations.

Tetracycline antibiotics are unstable under acidic and alkaline conditions. Tetracycline drugs contain many hydroxyl groups, enol hydroxyl groups, and carbonyl groups. They can form insoluble chelates with various metal ions under neutral conditions. Forms insoluble calcium or magnesium salts with calcium or magnesium ions, forms red complexes with iron ions, and forms yellow complexes with aluminum ions. In the body, the complex formed by the tetracyclines drug and calcium ions is deposited on the bones and teeth in yellow, which can cause yellowing of the teeth in children, and may cause tooth discoloration and bone growth inhibition in pregnant women. Therefore, children and pregnant women are cautious or banned from taking this medicine.

Tetracycline nucleus

Mechanism of Tetracycline Antibiotics

This product is a broad-spectrum bacteriostatic agent and has a bactericidal effect at high concentrations. In addition to common Gram-positive bacteria, Gram-negative bacteria and anaerobic bacteria, most Rickettsia, Mycoplasma, Chlamydia, Atypical Mycobacterium, and Borrelia are also sensitive to this product. This product has a better effect on Gram-positive bacteria than Gram-negative bacteria, but Enterococcus is resistant to it. Others such as Actinomyces, Anthrax, Listeria monocytogenes, Clostridium, Nocardia, etc. are sensitive to this product. This product has certain antibacterial activity against Neisseria gonorrhoeae, but penicillin-resistant Neisseria gonorrhoeae is also resistant to tetracycline. This product has good antibacterial effect on Gram-negative bacteria such as Vibrio, Yersinia, Brucella, Campylobacter, Yersinia, etc. It has no antibacterial activity against Pseudomonas aeruginosa, and it has certain antibacterial activity against some anaerobic bacteria. Effect, but far less than metronidazole, clindamycin and chloramphenicol, so it is not clinically chosen. For many years, due to the widespread application of tetracyclines, clinical common pathogenic bacteria including Gram-positive bacteria such as Staphylococcus and Gram-negative bacteria such as Enterobacter are most resistant to tetracycline, and cross-resistance exists among similar species. The action mechanism of this product is that the drug can specifically bind to the A position of the 30S subunit of the bacterial ribosome, preventing the aminoacyl-tRNA from binding at this position, thereby inhibiting the growth of the peptide chain and affecting the synthesis of bacterial proteins.

Main effects of tetracycline antibiotics

1. For the diagnosis of malignant tumors: Tetracycline has a strong affinity for cancer tissues in the stomach, lungs, bladder, oral mucosa and other parts. It enters the human body and is quickly taken up and accumulated by cancer cells. The concentration in blood is relatively low, and it is obtained from urine. Excretion is slower than normal. Utilizing the characteristic that tetracycline can fluoresce under the excitation of ultraviolet rays, the auxiliary diagnosis of the above malignant tumors is simple and easy, the patient has less pain, and the positive rate is more than 85%.

2. Used for various cysts: The salt tetracycline solution has a strong acidity and a pH of 2-3.5. It is used as a sclerosing agent to inject into the cysts of various cysts, which can cause hyperemic edema and fibrous infiltration in the serosa. Chemical inflammatory reactions, such as the destruction of pathological secretions of various serous fluids, promote chemical inflammatory reactions such as fiber exudation, disrupt the pathological secretions of various serous fluids, promote fibrotic adhesion, and close the cystic cavity. It is clinically used for sciatic tubercle cysts, moon kingdom follicle cysts, tendon sheath cysts, thyroid gland cysts, testicular and vestibular gland cysts, liver and kidney cysts, etc. The method is simple, the cure rate is high, and it can avoid surgical pain. It is currently the first choice for treatment Program. The conventional method is to immerse 0.25-0.5 g of the drug deeper than 2% lidocaine or procaine solution in 10-20 ml, and after taking out the cystic fluid, inject the medicine according to the size of the cyst as appropriate. Multiple cases can be divided into treatments and repeated medication. For example, inject 3 to 5 ml into the sciatic tubercle and Yue Guo Wo cyst, 0.5 to 1 ml for the tendon sheath cyst, 1 to 3 ml for the thyroid cyst, and 3 to 15 ml for liver and kidney cysts under the guidance of B ultrasound. . Ninety percent of the patients were cured with a single medication and applied up to three times without side effects.

3, treatment of refractory pleural effusion, effusion: refractory spontaneous pneumothorax often requires surgical repair, but the elderly are frail or have comorbidities, the risk of surgery is extremely great. For this, apply 0.5 g of this product, add 8 ml of 2% procaine, and then add 40 ml of 50% glucose, and slowly inject it into the chest of the affected side through a chest puncture or drainage tube 3, and continuously change the position within 4 hours, and then Drain the gas and fluid in the chest cavity. After 5 days, the chest radiograph can be repeated once without re-expansion. If the fracture is found under the guidance of fiberoptic bronchoscope, spray the liquor directly on the local area, and it will be cured within 1-5 days after operation. For various refractory pleural effusions, no matter tuberculous or cancerous, the injection of this agent may cause pleural cavity adhesion and occlusion to make pleural effusion disappear. After pumping the pleural effusion, inject 30-60 ml of tetracycline solution containing anesthetic, twice a week. Relapses are still effective, and it is suitable for promotion in grassroots units.

4. Treatment of bronchopleural fistula: Rinse the thoracic pus with normal saline, and then add 30 ml of normal saline with 0.5 g of this product, inject it through the catheter, drain after 6 hours, once every 3 days until healed.

5. Treatment of underarm odor: A local injection of a product can make the sweat glands and surrounding tissues atrophy and degeneration, reduce sweating and make underarm odor disappear. The method is to use a lidocaine solution containing tetracycline 3.3% -5% concentration, shave the axillary hair, and then divide the distribution of the axillary hair into two points at a 10-15 degree angle into the dermis and subcutaneous fascia. Inject 15 ml of medicine on each side. After observation in 300 cases, 296 cases were cured with one treatment and 4 cases were cured with 2 treatments.

6. Treatment of internal hemorrhoids: 0.25 g of this agent is dissolved in 6 millimeters of 2% procaine solution and injected into the intermucosal hemorrhoid venous plexus space of internal hemorrhoids, 2 ml per hemorrhoid nucleus. Observed 65 cases, all stopped bleeding after 1-3 times, hemorrhoids disappeared within 6-10 days.

7. Treating rhinoplasty: Velen is orally administered with tetracycline 0.25 g twice daily for a total of 8 weeks, and 75 patients are treated. The effect is better than topical 1% metronidazole cream. After treatment, it can obviously nourish acne-like damage and reduce erythema.

8. Bullous pemphigoid: Thorufelol found that 0.5-1.5 g / day of oral administration of this agent alone can be cured in 2-3 weeks. It is thought to be related to the inhibition of leukocyte chemotaxis and the inflammation of the basement membrane mediated by complement.

9. Treatment of acute acne-like lichen psoriasis: Shelley found that oral tetracycline 2.0 g / day for 1 month, treated 13 cases, only one case was ineffective, and the effect was similar to ultraviolet radiation therapy.

10. Treatment of acne: This agent can reach a high concentration in inflammatory sebum and hair follicles, which can reduce the amount of P. acnes on the skin, and directly inhibit extracellular lipase, so that acne improves. The usage is 0.25 g, taken orally four times a day. After the symptoms are improved, the dosage is reduced to 0.25-0.5 g / day, and the drug is gradually stopped.

11. Others: In recent years, it has been found that local injection of tetracycline in infants with chylothorax, cancerous pericardial effusion, hydrocele, esophageal varices bleeding, etc., also has good results, the method is basically the same as above.

Antibacterial effect of tetracycline antibiotics

Tetracyclines are broad-spectrum antibiotics that mainly inhibit bacterial protein synthesis, and have high bactericidal effects at high concentrations. It has a broad antibacterial spectrum and has antibacterial effects on Gram-negative aerobic and anaerobic bacteria, rickettsia, spirochaete, mycoplasma, chlamydia, and some protozoa. Tetracycline antibiotics have similar antibacterial activity, but minocycline and doxycycline have strong antibacterial activity against tetracycline-resistant strains.

Clinical application of tetracycline antibiotics

It is used for the clinical treatment of rickettsial disease, chlamydia disease, mycoplasma disease and spirochism disease. Doxycycline is generally preferred in clinical practice.

1. Rickettsia Infection: Tetracycline can be the first choice for typhus typhus, rat typhus, reburn typhus, rickettsial disease, and roundworm disease. It also has good curative effect on atypical pneumonia caused by Cox's rickettsia.

2. Chlamydia infection: Tetracycline is effective in treating psittaci fever caused by chlamydia psittaci, pneumonia caused by chlamydia pneumoniae, nonspecific urethritis cervicitis caused by chlamydia trachomatis, venereal lymphogranuloma, trachoma, etc. It is effective for oral or topical application. . Doxycycline is preferred.

3. Mycoplasma infection: It has good effect on atypical pneumonia and non-specific urethritis caused by Mycoplasma pneumoniae.

4. Borrelia infection: The most effective medicine is to treat chronic migratory erythema caused by Borrelia burgdorferi and regression fever caused by Treponema pallidum.

5. Bacterial infections: treatment of groin granuloma caused by C. granulomatosis, cholera caused by Vibrio cholerae, and brucellosis caused by Brucella are all drugs of choice.

Tetracycline antibiotic adverse reactions

(1) Gastrointestinal response: direct stimulation after oral administration can easily cause symptoms such as nausea, vomiting, abdominal pain, diarrhea, abdominal discomfort, and apparent loss of appetite. Although it can be reduced after meals, it affects drug absorption. The local irritation is large and can even cause esophageal ulcers.

(2) Double infection (alternative flora): It often occurs in frail, infants, and patients with glucocorticoids and antitumor drugs.

(3) Effect on bone and tooth growth

(4) Liver damage

(5) Vitamin deficiency

(6) Renal toxicity

In addition, tetracycline antibiotics can occasionally cause allergic reactions such as drug fever and rash.