Absorption and excretion of metronidazole after administration of metronidazole benzoate mixture.

Serum concentrations and urinary excretion of metronidazole after single dose therapy were investigated in patients with giardiasis. A metronidazole benzoate mixture was administered to 10 adults in total doses of 2 g and to 6 children in doses of approximately 50 mg/kg body weight. No unhydrolyzed metronidazole benzoate was found in the serum. The maximum serum concentrations of metronidazole averaged 30 microgram/ml. These values as well as estimated metronidazole absorption were approximately 30% lower than in 3 adult patients given single doses of 2 g of pure metronidazole in tablet form.