GENERIC NAME: metronidazole
BRAND NAME: Flagyl
DRUG CLASS AND MECHANISM: Metronidazole is an antibiotic effective against anaerobic bacteria and certain parasites. Anaerobic bacteria are single-celled, living organisms that thrive in environments in which there is little oxygen (anaerobic environments). Anaerobic bacteria can cause disease in the abdomen (bacterial peritonitis), liver (liver abscess), and pelvis (abscess of the ovaries and the Fallopian tubes).
Trichomonas is a vaginal parasite that causes inflammation of the vagina (vaginitis). Metronidazole selectively blocks some of the functions within the bacterial cells and the parasites resulting in their death.
The FDA approved metronidazole tablets in July 1963.
- Metronidazole is used to treat parasitic infections including Giardia infections of the small intestine, amebic liver abscess, and amebic dysentery (infection of the colon causing bloody diarrhea), bacterial vaginosis, trichomonas vaginal infections, and carriers of trichomonas (both sexual partners) who do not have symptoms of infection.
- Metronidazole is also used alone or in combination with other antibiotics in treating abscesses in the liver, pelvis, abdomen, and brain caused by susceptible anaerobic bacteria.
- Metronidazole is also used in treating infection of the colon caused by a bacterium called C. difficile. Many commonly-used antibiotics can alter the type of bacteria that inhabit the colon. C. difficile is an anaerobic bacterium that can infect the colon when the normal types of bacteria in the colon are inhibited by common antibiotics. This leads to inflammation of the colon (pseudomembranous colitis) with severe diarrhea and abdominal pain.)
- Metronidazole also is used in combination with other drugs to treat Helicobacter pylori (H. pylori) that causes stomach or intestinal ulcers.
- Metronidazole topical gel is used for treating acne rosacea.
- Metronidazole vaginal gel is used for treating bacterial vaginosis.
SIDE EFFECTS: Metronidazole is a useful antibiotic and is generally well tolerated with appropriate use.
Minor side effects include:
Serious side effects of metronidazole are rare and the drug should be stopped if these symptoms appear:
- Damage of nerves resulting in numbness and tingling of extremities
- Peripheral neuropathy
- Aseptic meningitis
Quick GuideSymptoms of Mono: Infectious Mononucleosis Treatment
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Need help identifying pills and medications?
Use the pill identifier tool on RxList.