Doxycycline binds with high affinity to the 30S ribosomal subunit near the A site, blocking aminoacyl-tRNA from docking and preventing elongation of the nascent peptide chain. Its lipophilic structure allows penetration into respiratory lining fluid, neutrophils, and intracellular compartments, supporting activity against atypical bacteria, rickettsiae, Borrelia, and community-acquired MRSA strains. Protein synthesis inhibition is primarily bacteriostatic, yet sustained tissue concentrations provide a prolonged post-antibiotic effect that is clinically useful in respiratory, skin, and tick-borne infections.