Metronidazole. How it Works

Metronidazole is a nitroimidazole anti-infective medication that is primarily used to treat infections caused by certain organisms — anaerobic bacteria and protozoa in particular. It is regarded as the gold standard anti-anaerobic agent.

Pfizer markets it in the United States under the brand name Flagyl, while Sanofi-Aventis uses the same brand name to market metronidazole worldwide. A number of generic manufacturers market it as well, offering it at a reduced price.


Metronidazole is used to treat the following infections:

* Intra-abdominal, including peritonitis, intra-abdominal abscess, and liver abscess
* Skin infections
* Bones and joints
* Bacterial septicemia
* Endocarditis
* Gynecologic (for example, endometritis, endomyometritis, tubo-ovarian abscess, and post-surgical vaginal cuff infection)
* Lower respiratory tract (in combination with another agent with activity against microaerophilic Streptococcus)
* Additional treatment for gastritis and duodenal ulcer involving Helicobacter pylori
* Central nervous system (meningitis and brain abscess)
* Bacterial vaginosis
* Giardiasis
* Trichomoniasis
* Amebiasis

How it works

Metronidazole enters an aerobic bacterium where, via the electron transport protein ferrodoxin, it is lowered. DNA breakage occurs after the drug binds to DNA. In vitro data indicates that metronidazole exhibits antioxidant attributes and may help prevent and treat the symptoms of rosacea.


The benefits of metronidazole include:

* High percentage of sensitive Gram-negative anaerobes
* It is available in both oral and intravenous forms
* Kills bacteria quickly
* Penetrates tissue well
* Considerably small chance of causing C. difficile colitis
* Cost


* Metronidazole hydroxy metabolite can potentially cause cancer. It has also been proven that metronidazole can cause cancer in animals. The medication should not be used unless absolutely necessary.

* Using alcohol in conjunction with metronidazole can cause a disulfiram-like reaction characterized by nausea, vomiting, flushing of the skin, tachycardia (accelerated heart rate), shortness of breath, and possibly death. Alcohol should not be consumed while undergoing systemic metronidazole therapy. Allow at least 24 hours to pass upon completion of therapy before consuming alcohol.

* Gastrointestinal tract symptoms can result from acute toxicity. Neurological damage can occur as a result of chronic toxicity. Convulsive seizures and peripheral neuropathy may occur.