Pharmacokinetics and therapeutic efficacy of metronidazole at different dosages

Metronidazole, a drug effective against certain protozoal and anaerobic infections, was given female patients with Trichomoniasis urogenitalis. Group I received twice daily 250 mg of metronidazole (supplied as 250 mg tablets Vagimid). Group II received in a single dose 1.0 g (4 tablets); and group III, 2.0 g (8 tablets). Serum and urine metronidazole levels were measured polarographically. Kinetic parameters were determined from the measured values of the concentration time curve by a computing program. An exact control of the therapeutic result was carried out. In all patients peak serum levels occurred within 1-3 hr and averaged 5.1 +/- 1.7 microgram/ml after 250 mg doses, 19.6 +/- 3.8 microgram/ml after 1.0 g doses and 40.6 +/- 9.3 microgram/ml after 2.0 g doses. About 35% of the administered dose was recovered in the urine in 12 hr and about 50% in 24 hr. Metronidazole shows protein binding of 10-20% equally in vivo and in vitro. Minimum trichomonacidic concentrations of nearly 1 microgram/ml were still present 12 hr after oral application of 250 mg metronidazole, and 24 hr to 36 hr, respectively after 1.0 g and 2.0 g daily doses. The cure rate was 100%. No serious side effects ocurred in any of the patients.