Makroliden

Makroliden, or macrolides, are a class of antibiotics characterized by a large macrocyclic lactone ring. They are produced by certain actinobacteria, notably Saccharopolyspora erythraea, and include drugs such as erythromycin, azithromycin, clarithromycin, and roxithromycin. They act by binding to the 50S ribosomal subunit of bacteria, inhibiting translocation during protein synthesis, resulting in bacteriostatic activity.

Makroliden have activity primarily against Gram-positive cocci and atypical pathogens, including Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella species, as well as some Gram-negative organisms like Haemophilus influenzae. They are commonly used for respiratory tract infections, skin and soft tissue infections, and are alternatives for people with penicillin allergy. They are also used for some sexually transmitted infections and in patients with specific infections where macrolides are preferred.

Pharmacokinetic properties vary: erythromycin is acid-labile; azithromycin and clarithromycin have longer half-lives and better tissue penetration. Macrolides are often metabolized by the liver and may interact with other drugs, notably via inhibition of cytochrome P450 enzymes, especially erythromycin and clarithromycin, leading to dose adjustments for concomitant medications.

Resistance commonly arises from methylation of the 23S rRNA binding site (erm genes) and from efflux pumps (mef genes), diminishing binding. Side effects include gastrointestinal upset, QT interval prolongation, and rare hepatotoxicity. They should be used judiciously to minimize resistance and adverse effects; stewardship guidelines limit unnecessary use.