Penicillin G, is also known as penicillin, dispensin, penicillin sodium, benzylpenicillin sodium, penicillin potassium, benzylpenicillin potassium. Penicillin is a kind of antimicrobial, is a class of antibiotics containing penicillanes in the molecule, which can destroy the cell wall of bacteria and play a bactericidal role in the reproduction phase of the bacterial cell, and it is an antibiotic extracted from penicillin molds. Penicillin belongs to the ? -lactam antibiotics (? -lactams).
Second, classification
According to its characteristics can be divided into:
Penicillin G class: such as penicillin G potassium, penicillin G sodium, longacting cillin, penicillin G, peillinG, penicillin, penicillin sodium, benzylpenicillin sodium, penicillin potassium, benzylpenicillin potassium, etc..
Penicillin V: (alias: phenoxymethylpenicillin, 6-phenoxyacetamido penicillanic acid) such as penicillin V potassium, etc. (including there are a variety of dosage forms).
Enzyme-resistant penicillin: such as benzathine penicillin (new penicillin II), chlorazolyl penicillin and so on.
Ampicillin class: such as ampicillin, amoxicillin, etc..
Anti-pseudomonas penicillin: such as carbenicillin, piperacillin, ticarcillin and so on.
Mecillin and its ester picillin: such as mecillin and its ester pimecillin, etc., which is characterized by more enzyme-resistant, effective against certain negative bacilli (eg, colorectal, Klebsiella and Salmonella), but poorly effective against Pseudomonas aeruginosa.
Methicillin: such as tamoxifen, etc.
Third, the antibacterial effect
Penicillin G antibacterial effect is very strong, in the bacterial reproduction period of the low concentration of bacteriostatic, the higher concentration of bactericidal. High antimicrobial activity against pathogenic bacteria: ① most G + cocci, such as hemolytic streptococci, pneumococci, Streptococcus grass green, sensitive Staphylococcus aureus and Staphylococcus epidermidis, etc.; ② G + bacilli, such as diphtheria Corynebacterium, Bacillus anthracis, Clostridium perfringens, Clostridium tetani, Lactobacillus and so on; ③ (T-cocci, such as Neisseria meningitidis, sensitive Neisseria gonorrhagicae and so on; ④ a small number of CT bacilli, such as Influenza bacillus, Bordetella pertussis, etc.; ⑤ spirochetes, actinomycetes, such as spirochetes of syphilis, leptospira, leptospira regnans, bovine actinomycetes. Weak effect on most (T bacilli, insensitive to enterococci, no effect on fungi, protozoa, rickettsiae, viruses and so on. Staphylococcus aureus, Neisseria gonorrhoeae, pneumococcus, Neisseria meningitidis, etc. are highly susceptible to resistance to this drug.
Fourth, adverse reactions
1. Metamorphosis is the most common adverse reaction of penicillin, the first in a variety of drugs, I, II and III type of metamorphosis of the total incidence of 3% to 10%. Various types of allergic reactions can occur, with type Ⅱ that is hemolytic anemia, drug rash, contact dermatitis, interstitial nephritis, asthma and melon type that is serum sickness-like reaction is more common, but more than not serious, can disappear after stopping the drug. The most serious is type I, i.e. anaphylaxis, the incidence of which accounts for (0.4-1.5)/10,000 of the number of people who use the drug, with a mortality rate of about 0.1/10,000 people. The cause of allergic reaction is the degradation product of penicillin solution, penicillin thiazole protein, penicillinenoic acid, 6-APA polymer due to the body after exposure to 5?8 days to produce antibodies, when re-exposed to produce allergic reaction. Most of the drug users occur immediately after exposure to the drug, and a few people can occur a few days later. The clinical manifestations of anaphylaxis patients are mainly circulatory failure, respiratory failure and central depression.
The main preventive measures: ① carefully inquire about the history of allergy, penicillin allergy is prohibited; ② to avoid abuse and local use of the drug; ③ to avoid injection of penicillin in the hungry; ④ not in the absence of first aid medication (such as epinephrine) and rescue equipment under the conditions of use; ⑤ the first time to use, the interval of more than 3 days or change the batch number of the person must be done to skin allergy test, a positive reaction is prohibited; ⑥ injections to be used now; ⑦ patients need to use Now with; ⑦ patients need to be observed for 30 minutes after each use of the drug, no reaction before leaving; ⑧ once anaphylaxis occurs, should be the first immediate subcutaneous or intramuscular injection of epinephrine 0.5?1.0mg, the serious cases should be diluted slowly static or drip, if necessary, add glucocorticoids and antihistamines. At the same time using other first aid measures.
2. Herxheimerreaction (Herxheimerreaction) when applying penicillin G to treat infections such as syphilis, leptospirosis, rat-bite fever, or charcoal jaundice, there can be an exacerbation of symptoms, manifested as generalized malaise, chills, fever, sore throat, myalgia, rapid heartbeat and other symptoms. This reaction may be caused by a large number of pathogens released after being killed.
3. Other adverse reactions Intramuscular injection of penicillin G may produce local pain, redness, swelling or hardness. Overdose or rapid intravenous administration can produce direct irritation of the cerebral cortex. Intrathecal injection may cause meningeal or neurologic irritation.
V. Interactions
1. Probenecid, aspirin, indomethacin, and prednisone can competitively inhibit ? -lactam antibiotics from the renal tubule secretion, so that the excretion is slowed down, the blood concentration increases, can enhance the ? -lactam antibiotics, and prolong the duration of action.
2. and aminoglycoside antibiotics have a synergistic antibacterial effect, the antibacterial spectrum is expanded, the antibacterial mechanism is different and the antibacterial activity is strengthened. However, it can not be mixed with intravenous drug administration to prevent interactions leading to a decrease in efficacy.
3. Sulfonamides, erythromycins, tetracyclines, chloramphenicol and other antibacterial drugs are used in combination with antibiotics. -The combination of sulfonamides, erythromycins, tetracyclines, chloramphenicol and other antibacterial drugs with ? -Lactam antibiotics are bacteriostatic drugs in the reproductive phase, bacteriostatic drugs inhibit bacterial reproduction, and the bacteriostatic effect of the antibiotics can be antagonistic to the antibiotic. The bactericidal effect of -lactam antibiotics is obviously inhibited.
4. -Lactam antibiotics can not be paired with heavy metals, especially copper, zinc, mercury, so as not to affect its activity.
5. -Lactam antibiotics can not be mixed with lincomycin, tetracycline, vancomycin, erythromycin, amphotericin B, norepinephrine, mesalamine, phenytoin sodium, isopropylzine, vitamin B, vitamin C and so on and then given intravenously, or else it is easy to cause turbidity of the solution.
6. Amino acid nutrient solution can enhance the ? -antigenicity of lactam antibiotics, is a contraindication to pairing.
7.