rifapentine + azithromycin

**rifapentine + azithromycin** is a combination of two small molecule antibiotics: rifapentine, a rifamycin-class antibiotic, and azithromycin, a macrolide antibiotic. This combination is not a branded or widely marketed co-formulation but represents the concurrent use of both drugs, sometimes studied for enhanced antimicrobial efficacy. Each drug has a distinct mechanism of action: rifapentine inhibits DNA-dependent RNA polymerase, thereby blocking bacterial RNA synthesis, while azithromycin binds to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis. Experimental and preclinical studies have investigated the combination, notably for enhanced activity against certain *Chlamydia* and *Mycobacterium* species, although clinical data are limited. This combination is not FDA approved as a fixed-dose product but may be used off-label or experimentally in research settings[1][3].