Antiprotozoal and antimicrobial drug, a derivative of 5-nitroimidazole. The mechanism of action is the biochemical reduction of the 5-nitro group of metronidazole by intracellular transport proteins of anaerobic microorganisms and protozoa. The reduced 5-nitro group of metronidazole reacts with the DNA of a cell of microorganisms, inhibiting the synthesis of their nucleic acids, which leads to the death of bacteria.
Active with respect to Trichomonas vaginalis, as well as Gram-negative anaerobes Bacteroides spp. (incl. Bacteroides fragilis, Bacteroides distasonis, Bacteroides ovatus, Bacteroides thetaiotaomicron, Bacteroides vulgatus), Fusobacterium spp. and some Gram-positive microorganisms (sensitive strains Eubacterium spp., Clostridium spp., Peptococcus spp., Peptostreptococcus spp.). The MIC for these strains is 0.125-6.25 μg / ml.
With external application has anti-acne action, the mechanism of which is precisely unknown (not related to the action on the mite Demodex folliculorum, found in the hair follicles and the secretion of the sebaceous glands, and any influence on the production of this secret).
Metronidazole for external use may have antioxidant activity.It is established that it significantly reduces the production of active oxygen, hydroxyl radicals and hydrogen peroxide by neutrophils, which are potential oxidants capable of causing tissue damage at the site of inflammation. Metronidazole for external use is ineffective against telangiectasias seen in rosacea.
Metronidazole is insensitive to aerobic microorganisms and facultative anaerobes, but in the presence of mixed flora (aerobes and anaerobes) metronidazole acts synergistically with antibiotics effective against conventional aerobes.