Studies on the metabolism of metronidazole

We have investigated the metabolic products of Flagyl excreted in the urine of patients. 1. Unchanged Flagyl was excreted to some extent by all patients examined. 2. An acidic oxidation product and several conjugates were excreted. 3. A fluorescent, lipophilic product whose nature was discussed was excreted. 4. The dark urine excreted by some patients contained an azo dye resulting from a bimolecular condensation of Flagyl metabolites.