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.

Erythromycin is a macrolide antibiotic of bacteriostatic action. In high concentrations and relatively high-sensitivity microorganisms may have a bactericidal effect.

Zithromax - antibiotic of a wide spectrum of action. Antibiotic-azalide, a representative of a new subgroup of macrolide antibiotics. In the focus of inflammation it has a bactericidal effect. For the active ingredient of Zithromax, Azithromycin, all the gram-positive cocci (except those bacteria which are resistant to erythromycin) are susceptible.