Acute Exacerbation of Chronic Bronchitis Malaria Prophylaxis Anthrax Sexually Transmitted Disease Chlamydia trachomatis Lymphogranuloma venereum Pelvic Inflammatory Disease III. Contraindications Pregnancy IV. Mechanism SeeTetracyclines V. Precautions AAP now approves Doxycycline for ANY age up to 21 day duration...