Metronidazole brain abscess

Metronidazole is indicated for treatment of anaerobic or mixed intra-abdominal infections, vaginitis (trichomonas infection, bacterial vaginosis), C difficile colitis, and brain abscess. The typical dosage is 500 mg three times daily orally or intravenously (30 mg/kg/d). Vaginitis may respond to a single 2-g dose. A vaginal gel is available for topical use. 

An exception is the B. fragilis group, 75% of which may be resistant. Pulmonary and periodontal infections usually respond well to penicillin G. Mild-to-moderate infections at these sites may be treated with oral medication (either penicillin G or penicillin V 400,000 units four times daily). More severe infections should be treated with 12-20 million units of penicillin G intravenously. Brain abscesses also frequently contain several species of anaerobes, and most experts use high doses of penicillin G (20 million units per day) plus metronidazole or chloramphenicol. 

Although many infections with gram-positive cocci respond to clindamycin, the high incidence of diarrhea and the occurrence of pseudomembranous colitis limit its use to infections where it is clearly superior to other agents. Clindamycin is particularly valuable for anaerobic infections, especially those due to B. fragiUs. Clindamycin is not predictably useful for the treatment of bacterial brain abscesses metronidazole, in combination with penicillin or a third-generation cephalosporin, is preferred. 

---