Azithromycin Powder CAS 83905-01-5

Erythromycin has weak antibacterial activity and a narrow antibacterial spectrum. It is only effective against gram-positive bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes, as well as atypical pathogens such as Mycoplasma pneumoniae, Chlamydia, and Legionella. It has little effect on gram-negative bacteria and anaerobic bacteria, and bacteria are prone to resistance to it.

Azithromycin has been structurally modified to enhance its antibacterial activity against Gram-positive bacteria and atypical pathogenic bacteria, as well as against Gram-negative bacteria such as Haemophilus influenzae, Moraxella catarrhalis, Escherichia coli, Klebsiella pneumoniae, and fragile Anaerobic bacteria such as Bacteroides have strong antibacterial activity and are not easy to develop drug resistance.

Erythromycin is clinically mainly used to treat acute upper respiratory tract infections such as acute tonsillitis, acute pharyngitis, and sinusitis, lower respiratory tract infections such as pneumonia, acute bronchitis, and skin and soft tissue infections, while azithromycin has an expanded antimicrobial spectrum and a more tissue distribution. It is widely used in the treatment of urogenital system infections such as simple gonorrhea in addition to acute upper and lower respiratory tract infections and skin and soft tissue infections.

Erythromycin is unstable to acid, easily destroyed by gastric acid and inactivated, and has poor absorption after oral administration. Therefore, oral erythromycin used clinically is usually made into enteric-coated preparations (enteric-coated tablets or enteric-coated capsules). The preparation generally needs to be taken on an empty stomach or before meals, and erythromycin has a short half-life and short bacteriostatic effect, and needs to be administered 3-4 times a day, while azithromycin is stable to acid, high oral bioavailability, long half-life, bacteriostatic It has a long duration of action and only needs to be administered once a day, which improves the compliance of patients with medication.

Erythromycin is common in nausea, vomiting, diarrhea, abdominal pain, loss of appetite and other gastrointestinal reactions, hearing damage, liver damage, and occasionally severe skin allergic reactions and arrhythmias, with a high incidence of adverse reactions, while azithromycin has a low incidence of the above-mentioned adverse reactions , well tolerated.