Snapshot A 22-year-old woman presents to her gynecologist for a wellness visit. She does not report any acute complaints. She denies any abnormal vaginal discharge, bleeding, lesions, or odors. She is currently sexually active with multiple men and infrequently uses barrier contraception; however, she has an intrauterine device. Pelvic examination is unremarkable. Laboratory testing is notable for a nucleic acid amplification test that is positive for gonorrhea and chlamydia. She is started on intramuscular ceftriaxone and oral azithromycin. Introduction Mechanism of action impairs bacterial protein synthesis by binding to the 50S ribosomal subunit inhibits transpeptidation, translocation, and chain elongation Medications azithromycin clarithromycin erythromycin Mechanism of resistance methylation of the 23 rRNA-binding site Clinical use atypical pneumonia Mycoplasma Chlamydia Legionella sexually transmitted infections (Chlamydia) gram-positive cocci B. pertussis Adverse effects gastrointestinal upset QT prolongation acute cholestatic hepatitis eosinophilia rash P-450 inhibition (clarithromycin and erythromycin)