The tetracyclines.

The tetracyclines, among the first of the antibiotics to become available 50 years ago, remain widely used. Tetracyclines have bacteriostatic activity against a wide variety of pathogens that are responsible for many common and some exotic infections. They are particularly valuable in the treatment of atypical pneumonia syndromes, chlamydial genital infections, rickettsial infection (Rocky Mountain spotted fever, typhus, Q fever), Lyme disease, and ehrlichiosis. On the basis of pharmacokinetic considerations, doxycycline is the preferred agent among the tetracycline congeners. Minocycline may have a limited role in the treatment of methicillin-resistant staphylococcal disease in situations in which an oral antimicrobial agent may be appropriate. The tetracyclines are generally contraindicated during pregnancy and childhood because of their association with dental staining and interference with bone growth. Photosensitivity may occur with some tetracyclines, and several drug and food interactions may limit gastrointestinal absorption.