Tetracyclines.

Tetracyclines are relatively safe drugs with a broad antimicrobial spectrum. Doxycycline remains the preferred tetracycline agent for most indications. Doxycycline has a long half-life, which makes convenient twice-a-day dosing possible. It is well absorbed orally even in the presence of food, has excellent tissue penetration, and does not require a dose adjustment in renal insufficiency. Doxycycline is a useful agent for the treatment of atypical pneumonias, sexually transmitted diseases, traveler's diarrhea, rickettsial infections, and Lyme disease. Minocycline is the preferred drug for MRSA colonization/infection.