Metronidazole (Flagyl) - A guide and description for use

Metronidazole

Metronidazoleis a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. It is marketed by Pfizer under the trade name Flagyl in the US, while Sanofi-Aventis markets metronidazole globally under the same tradename, Flagyl, and also by various generic manufacturers, who sell it at a lower price.

Metronidazole, taken up by diffusion, is selectively absorbed by anaerobic bacteria and sensitive protozoa. Once taken up by anaerobes, it is non-enzymatically reduced because of lowered ferredoxin, which is produced by the action of pyruvate:ferredoxin oxido-reductase. This reduction causes the production of toxic products to anaerobic cells, and allows for selective accumulation in anaerobes.

Dosages

Bacterial anaerobes 150 mg/kg PO weekly
Amoebiasis 24-50mg/kg PO rep q 2 wks
40mg/kg PO rep q 2 wks
125mg/kg PO rep q 2 wks
Flagellates 25-50mg/kg PO rep in 3-4 d PRN

Specific to chelonia:
Amoebiasis, Trichomoniasis 50 mg/kg PO; rep 2 wks