Azithromycin – more than an antibiotic

Abstract

Azithromycin, which belongs to the azalide subclass, is a derivative of erythromycin, obtained by inserting a methyl substituted nitrogen atom into the lactone ring. In this way, better stability at the low pH of the gastric juice, improved bioavailability, and an extended half-life relative to erythromycin were achieved. The mechanism of azithromycin antibacterial activity is to inhibit bacterial cell protein synthesis by binding to the 50S ribosomal subunit and preventing bacterial mRNA translation and protein biosynthesis. In addition to bactericidal activity, azithromycin also has immunomodulatory, anti-inflammatory, and antiviral properties. For this reason, it is used in exacerbations of asthma and chronic obstructive pulmonary disease. However, its antibacterial efficacy and high safety are most important. In clinical practice, several model clinical profiles of patients can be presented: children with community-acquired Mycoplasma pneumoniae pneumonia, recurrent respiratory tract infections and exacerbations of chronic inflammations, acute bronchitis of likely bacterial aetiology, tonsillitis and allergy to β-lactam antibiotics, and pertussis. Efficacy has also been proven in primary skin and soft tissue infections as well as erysipelas. However, azithromycin may also have an unusual use, as confirmed by recent reports. These include travellers’ diarrhoea, cat scratch disease (bartonellosis – rickettsiosis), and mycobacteriosis (nontuberculous mycobacteria). Appropriate spectrum of action, efficacy and safety, as well as a low percentage of resistant bacteria, good bioavailability, easy to remember, practical and simple dosage regimen and optimal cost are features of a good antibiotic. Azithromycin is close to meeting all these criteria.