Metronidazole

Metronidazole is a nitroimidazole antibiotic first isolated in the 1950s. Many nitroimidazoles were being studied at the time, as the class was found to have trichomonacidal properties. Metronidazole was of particular interest due to its high activity against Trichomonas vaginalis and Entamoeba histolytica both in vitro and in vivo as well as clinical activity against many anaerobic pathogens including Gram-positive and Gramnegative bacteria and Giardia lamblia. Metronidazole is often used clinically for intra-abdominal infections and is the firstline treatment for Clostridium difficile–associated diarrhea.

Metronidazole is an odorless, white, yellow, or cream-colored crystalline solid. Darkens on exposure to light. Bitter, salty taste (do not test). Soluble in hot water, slightly soluble in ethanol, slightly soluble in water or chloroform, very slightly soluble in ether.

ChEBI: Metronidazole is a member of the class of imidazoles substituted at C-1, -2 and -5 with 2-hydroxyethyl, nitro and methyl groups respectively. It has activity against anaerobic bacteria and protozoa, and has a radiosensitising effect on hypoxic tumour cells. It may be given by mouth in tablets, or as the benzoate in an oral suspension. The hydrochloride salt can be used in intravenous infusions. Metronidazole is a prodrug and is selective for anaerobic bacteria due to their ability to intracellularly reduce the nitro group of metronidazole to give nitroso-containing intermediates. These can covalently bind to DNA, disrupting its helical structure, inducing DNA strand breaks and inhibiting bacterial nucleic acid synthesis, ultimately resulting in bacterial cell death. It has a role as an antitrichomonal drug, a prodrug, an antibacterial drug, an antimicrobial agent, an antiparasitic agent, a xenobiotic, an environmental contaminant, a radiosensitizing agent and an antiamoebic agent. It is a member of imidazoles, a C-nitro compound and a primary alcohol. It is a conjugate base of a metronidazole(1+).

White to pale-yellow crystalline powder with a slight odor. Bitter and saline taste. pH (saturated aqueous solution) about 6.5.

Confirmed carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenic data. Moderately toxic by ingestion, intraperitoneal, and subcutaneous routes. Human systemic effects by ingestion: paresthesia, nerve or sheath structural changes, eye changes, tremors, fever, jaundice and other liver changes, hearingacuity changes, somnolence, and ataxia. Experimental reproductive effects. Human mutation data reported. When heated to decomposition it emits toxic fumes of NOx.

Metronidazole is the drug of choice for amebiases, vaginal trichomonasis and trichlomonadic urethritis in men, lambliosis, amebic dysentery, and anaerobic infections caused by microorganisms that are sensitive to the drug. Synonyms of this drug are flagyl, protostat, trichopol, and vagimid.

Metronidazole is available as oral, intravaginal, topical, and parenteral preparations. It is manufactured by several companies, but is only available by prescription. Unintentional environmental exposure is unlikely, and if it occurs, it is very unlikely to cause toxicity.

Used as an antibacterial in the treatment of rosacea. Antiprotozoal (trichomonas). A potential human carcinogen.

Metronidazole, is an antibiotic and antiprotozoal agent. It is mainly used to treat or prevent systemic or local infections caused by anaerobic bacteria, such as anaerobic bacterial infections in the abdominal cavity, digestive tract, female reproductive system, lower respiratory tract, skin and soft tissues, bones and joints, etc. Inflammation, meningeal infections, and colitis caused by antibiotic use are also effective. Tetanus is often treated with tetanus antitoxin (TAT). It can also be used for oral anaerobic infection. On October 27, 2017, the list of carcinogens published by the World Health Organization's International Agency for Research on Cancer was preliminarily sorted for reference, and metronidazole was included in the list of class 2B carcinogens. In January 2020, metronidazole was selected into the second batch of national centralized drug procurement list.