Treatment of anaerobic infections with metronidazole

Metronidazole was used parenterally and orally to treat thirty patients with a variety of anaerobic and mixed infections. Other antimicrobial agents with activity against infecting anaerobes were not used or had failed. Sixteen patients (53%) were cured, thirteen (43%) were improved; and one (3%) failed to respond. Cultures during therapy disclosed no anaerobic pathogens in 24 of 26 (92%). Clinical failure (one patient) and the continuing presence of anaerobic pathogens (two patients) were associated with initially inadequate surgical procedures. Peak plasma levels achieved with doses of approximately 30 mg/kg/day in 26 patients were 21.0 ± 7.2 μg/ml. Slightly higher peak levels were achieved when this dose was preceded by a loading dose of 15 mg/kg. Side effects were infrequent and mild: pruritus with rash: 3 (10%); nausea: 5 (17%); and metallic taste: 2 (7%).