Metronidazole: Indications, side effects and contraindications

The group of nitroimidazole derivatives includes such drugs: tinidazole, nimorazole, pretomanid, megazol, azanidazole, ornidazole, dimetridazole, metronidazole.

The basis of nitroimidazoles is imidazole, which is converted by nitrification (with nitric and sulfuric acids) into 5-nitro-1H-imidazole.

Metronidazole is a drug with the formula 2-(2-methyl-5-nitroimidazol-1-yl) ethanol (IUPAC). Cream-colored crystalline powder with a slight odor, molar mass 171 g/mol, melting point 159-163 °C, solubility in water 11 g/l.

The most famous names of metronidazole are: flagyl, trichopolum.

Trichopolum contains the following chemical elements: carbon (42%), hydrogen (5.3%), nitrogen (24.5%), oxygen (28%).

Identifiers (registration codes) for metronidazole: CAS number: 443-48-1, EU number: 207-136-1, NSC number 757118, PubChem CID: 4173; DrugBank: DB00916; ChemSpider: 4029; KEGG: D00409; UNII: 140QMO216E; CheBI: 6909; NIAID ChemDB: 007953.

The story of metronidazole begins in 1955 when Nakumura discovers aomycin (nitroimidazole). In 1956, Hori demonstrates the antiprotozoal properties of nitroimidazole. In 1957, 5-NIMZ-metronidazole was synthesized. In 1960, this drug was first used to treat trichomonas infection, and in 1961 and 1969 for the treatment of giardiasis and balantidiasis.

The price of metronidazole varies between $0.00015/tablet in Iran to $1.83 in the UK.

Metronidazole can be administered orally, parenterally, rectally and topically.

Flagyl is readily absorbed in the intestines, and after 1 hour quickly forms high concentrations in the blood, which can be maintained for therapeutic purposes up to 6 hours. It spreads in various organs and tissues: in the central nervous system, liver, prostate gland, brain, lungs, bone tissue.

Metronidazole is excreted mainly in the urine (about 50%, according to other sources 10-20%), up to 50% is destroyed in the liver and about 7% is excreted in the bile.

Such microorganisms are sensitive to Trichopolum: balantidia, trichomonads, fusobacteria, clostridia, anaerobic cocci, bacteroids, amoeba, giardia.

Many aerobic bacteria are sensitive to metronidazole, including staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa.

The mechanism of action of metronidazole on anaerobic bacteria is that it acts on the RNA (ribonucleic acid) of the bacteria, destroying them.

Trichopol shows synergy with rifampicin and nalidixic acid.

Metronidazole is resistant to purulent exudate enzymes, for this reason it can be used for purulent wounds.

The use of flagyl in ulcerative and pseudomembranous colitis is due to the fact that it has a decongestant effect and stimulates the regeneration of the intestinal mucosa.

This medicine is used in the treatment of trichomoniasis in women and men, amoebic dysentery, giardiasis and balantidiasis.