makrolideja

Makrolideja are a class of antibiotics characterized by a macrocyclic lactone ring, typically containing 12 to 16 atoms, with one or more deoxy sugars attached. The best known member is erythromycin, and newer drugs such as azithromycin and clarithromycin have broadened the clinical uses of this class. Macrolides are produced by actinomycete bacteria, including Saccharopolyspora erythraea.

The primary mechanism of action is binding to the 50S subunit of the bacterial ribosome, which interferes with translocation during protein synthesis. This leads to predominantly bacteriostatic effects, although some organisms may be killed at higher drug concentrations. Macrolides generally have good activity against Gram-positive cocci and atypical pathogens such as Mycoplasma and Chlamydophila, with azithromycin and clarithromycin offering better tissue penetration and activity against certain intracellular pathogens. They are less active against many Gram-negative enteric bacteria, though combinations with other agents extend usefulness in some infections.

Pharmacokinetics vary among macrolides. Erythromycin is acid-labile and has significant drug interactions due to inhibition of cytochrome P450 3A4. Azithromycin and other newer macrolides tend to have longer half-lives and lower potential for drug interactions, with extensive tissue distribution. Resistance can arise via methylation of the 23S rRNA, reducing binding of the drug (erm-mediated MLSB resistance), or by efflux pumps (mef genes).

Clinical use includes respiratory tract infections, skin and soft tissue infections, and certain sexually transmitted infections, especially in patients with penicillin allergy. Common adverse effects are gastrointestinal upset, and rare hepatotoxicity or QT interval prolongation may occur.