Metronidazole was first introduced for the treatment of trichomoniasis. Now
, its therapeutics use has subsequently been expanded to include protozoal
and anaerobic infections. Oral administration is recommended: rosacea, peri
oral dermatitis, Helicobacter pylori, Trichomonas vaginalis and Giardia lam
blia infections and bacterial vaginosis.
Metronidazole given orally is absorbed almost completely. Metronidazole has
limited plasma protein binding but can reach very favourable tissue distri
bution, including central nervous system and placenta. This drug is extensi
vely metabolised by the liver to form 5 oxydative metabolites. The majority
of this drug and metabolites are excreted in urine and feces. The half-lif
e is 6 to io hours.
The recommended dose is 500 mg three time per day and an adaptation is nece
ssary in renal insufficiency. Metronidazole is well tolerated when administ
ered in dosages of less than 2 g per day. Some adverse reactions appear to
be related to the high dosages and treatment duration. Drug interactions wi
th alcohol, warfarin and phenytoin have been reported. Mutagenesis and canc
erogenesis is only described in mouse. Resistance, both clinical and microb
iological, has been described only rarely.