Pharmacokinetics of intravenous metronidazole in man

Metronidazole (500 mg) was infused over 20 min. to five patients. At the end of the infusion blood samples were drawn at brief intervals. After subsequent metronidazole analysis the curve plotted for the elimination of the drug showed a bi-exponential profile. Mean peak serum concentrations reached 15 micrograms per ml. At the end of the distribution phase, which was 20 to 30 min. after the infusion, the concentrations had fallen to 10 micrograms per ml. A two-compartment model was used to calculate the kinetic parameters. The elimination half-life ranged from 4.7 to 15.8 hours, the total clearance from 43 to 193 ml per min., and the peripheral distribution volume from 41.5 to 79.11 1. The areas under the serum level curves exhibited a four-fold variation, due to differences in either metabolism or elimination rate.