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The new macrolides: expanding the ways in antibiotic treatment
M L Avilés Santa1, C H Ramírez-Ronda
1Infectious Diseases Program, University of Puerto Rico School of Medicine, San Juan VA Medical Center 00927-5800.
Abstract:
After almost forty years of its introduction, erythromycin will not be the exclusive member of the macrolide group of antibiotic agents, but a new generation of its derivatives which surpass it in pharmacological properties and clinical efficacy will also be available. Clarithromycin, a 14-membered derivative, has shown acid stability, longer half-life, lower protein binding and higher lung tissue penetration. Its exceedingly high activity against erythromycin-susceptible gram-positive cocci, Mycoplasma pneumoniae, and Legionella pneumophila makes it and important alternative choice in the therapy of respiratory tract infections. Also, it has shown high activity against Chlamydia trachomatis, and high urinary clearance of this unmetabolized molecule, important properties which would render it a special role in the treatment of genitourinary tract infections. Azithromycin, a 15-membered derivative has shown enhanced basicity (due to the nitrogen atom in its lactone ring), longer half-life and lower protein bindings. Its exceptional activity against Hemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, Ureaplasma urealyticum and gram-negative bacteria, and its high concentration in tonsillar, pulmonary, prostatic and female reproductive tract tissues, assigns it an honorific place among the macrolides in the therapy against respiratory tract and genitourinary tract infections. Its role against T. gondii deserves further study, but points out this agent as a promise against this parasite.
Insights
New macrolide antibiotics like clarithromycin and azithromycin offer improved properties over erythromycin. These advanced antibiotics are effective against various respiratory and genitourinary infections.
Area of Science:
- Pharmacology
- Microbiology
- Infectious Diseases
Background:
- Erythromycin, a foundational macrolide antibiotic, has been in use for nearly four decades.
- Newer macrolide derivatives demonstrate superior pharmacological profiles and clinical effectiveness.
- This evolution necessitates an updated understanding of macrolide antibiotic applications.
Purpose of the Study:
- To compare the pharmacological properties and clinical efficacy of erythromycin derivatives, clarithromycin and azithromycin.
- To highlight the therapeutic advantages of these newer macrolides in treating specific infections.
- To identify key applications for clarithromycin and azithromycin in respiratory and genitourinary medicine.
Main Methods:
- Comparative analysis of pharmacological data (acid stability, half-life, protein binding, tissue penetration).
- Evaluation of antimicrobial activity against key pathogens (Gram-positive cocci, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia trachomatis, Hemophilus influenzae, etc.).
- Assessment of pharmacokinetic properties including tissue distribution and urinary clearance.
Main Results:
- Clarithromycin exhibits acid stability, a longer half-life, reduced protein binding, and enhanced lung penetration, proving effective against respiratory pathogens and Chlamydia trachomatis.
- Azithromycin, with increased basicity and longer half-life, shows potent activity against Gram-negative bacteria and key respiratory/genitourinary pathogens, with high tissue concentrations.
- Both agents present significant advantages over erythromycin for specific therapeutic indications.
Conclusions:
- Clarithromycin and azithromycin represent significant advancements in macrolide antibiotic therapy.
- These derivatives offer improved efficacy and broader applications in treating respiratory and genitourinary tract infections.
- Further research into azithromycin's potential against Toxoplasma gondii is warranted.