Metronidazole

The mechanism of action of antibiotic metronidazole is by diffusion. This is taken by the anaerobic bacteria and selective protozoa. Inside the anaerobic bacteria it is reduced non enzymatically. The reduction is takes place by the reaction with the reduced Ferritin generated by the pyruvate ferredoxin oxido reductase. The reduction causes production and accumulation of toxic products inside the anaerobes.

The organisms sensitive to metronidazole are anaerobic bacteria like Bacteroides fragilis, Fusobacterium spp.Clostridium spp, Peptostreptococcus spp and Prevotella spp, Helicobacter pylori, protozoa like Trichomonas vaginalis, Entamoeba histolytica and Giardia lamblia.

Metronidazole is used in the treatment of Trichomoniasis where both the partners are treated with metronidazole, in pelvic inflammatory disease, any abscess, peptic ulcer due to H. pylori, amoebic liver abscess, amoebiasis, giardiasis, gingivitis, oral ulcers, dental infections, brain abscess, peritonitis, tubo- ovarian abscess, lung abscess and non specifically in Crohn’s disease.

The adverse or the side effects of metronidazole are nausea, diarrhea, metallic taste in the mouth, thrombophlebitis when administered intravenously, hypersensitive reactions like rash, flushing, fever, headache, vomiting, glossitis and stomatitis. Long term use causes black hairy tongue, leucopenia, neutropenia and peripheral neuropathy.

Metronidazole is given in the dose of 250 to 400 mg tablets thrice daily. It is also available as intravenous solution at a dose of 500mg/ 100 ml, as metronidazole gels in the treatment of bacterial vaginosis and metronidazole creams in the treatment of acne rosacea.

It is contraindicated in pregnancy and during lactation due to the fear of damage caused to the fetus and the nursing baby. There is also a version of metronidazole for dogs and cats where it is commonly used to treat similar conditions..