Doxycycline is a semi-synthetic antibiotic of a broad spectrum of tetracyclines. Causes bacteriostatic action by suppressing protein synthesis of pathogens as a result of blocking the aminoacyl transport RNA (tRNA) with the "information RNA (rRNA) complex" ribosome.

Cefadroxil - cephalosporin antibiotic of the I generation for intake. It works as bactericidal, breaking synthesis of a cell wall of microorganisms. It has a broad spectrum of activity: it is active in relation as gram-positive (Staphylococcus spp. which don't produce and produce a penicillinase; Streptococcus spp. (including Streptococcus pneumoniae), Corynebacterium diphtheriae, Bacillus anthracis), and gram-negative microorganisms (Shigella spp., Salmonella spp., Escherichia coli, Haemophilus influenzae, Klebsiella spp., some strains of Proteus spp., especially Proteus mirabilis), Moraxella catarrhalis (Branhamella). Many strains of Enterococcus faecalis and Enterococcus faecium are steady against Cefadroxil.