Small molecule
PubChem CID 4173
Metronidazole
Flagyl
- Mechanism of action
- Nitroimidazole, forms DNA-damaging free radicals inside anaerobic bacteria/protozoa
- In plain language
- Gets switched on inside oxygen-free bacteria and parasites, where it damages their DNA and kills them.
- How it works
- Metronidazole, a nitroimidazole, exerts antibacterial effects in an anaerobic environment against most obligate anaerobes. After entering the organism by passive diffusion, the drug is activated in the cytoplasm of susceptible anaerobic bacteria through intracellular electron-transport proteins such as ferredoxin, which transfer an electron to its nitro group and form a short-lived nitroso free radical; this alteration creates a concentration gradient that promotes further intracellular drug uptake. The reduced form of metronidazole and its free radicals interact with DNA, inhibiting DNA synthesis and causing DNA degradation that leads to bacterial death. The label states plainly that the precise mechanism of action of metronidazole is unclear, and notes that metronidazole does not possess clinically relevant activity against facultative anaerobes or obligate aerobes.
- Therapeutic applications
- Indicated for symptomatic and asymptomatic trichomoniasis (T. vaginalis infection) in females and males, with simultaneous treatment of asymptomatic sexual partners recommended to prevent reinfection. Indicated for acute intestinal amebiasis (amebic dysentery) and amebic liver abscess, though therapy does not eliminate the need for aspiration or drainage of an abscess. Indicated for serious infections caused by susceptible anaerobic bacteria, including intra-abdominal infections (peritonitis, intra-abdominal abscess, liver abscess), skin and skin-structure infections, gynecologic infections (endometritis, tubo-ovarian abscess, postsurgical vaginal cuff infection), bacterial septicemia, bone and joint infections as adjunctive therapy, CNS infections including meningitis and brain abscess, lower respiratory tract infections, and endocarditis, when caused by susceptible organisms such as Bacteroides fragilis group, Clostridium, Eubacterium, Peptococcus, Peptostreptococcus, or Fusobacterium species. In mixed aerobic-anaerobic infections, an antimicrobial active against the aerobic component should be added.
- Class
- Small molecule
- Therapeutic area
- Antibiotic / Antiprotozoal
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