Study of gastric elimination of ornidazole after intravenous administration in patients undergoing digestive surgery

: In a previous study, performed in patients undergoing gastrointestinal surgery receiving antibiotics intravenously we pointed out that the gastric aspiration was an additional route of elimination for some drugs. In order to estimate the extra-dose required to replace losses in patients receiving ornidazole, a study was set up. 8 patients entered the trial; the patients were infused 500 mg of ornidazole for 3 days every 12 hours. Blood was sampled at 0-2-4-8-24 h after the last infusion. Urines and gastric aspirate were collected. The results indicate that the amount aspirated through the tubings is 69.1 +/- 37.5 mg per 24 hours (24.8 - 116.8) with a very high variability; the half-life was not different of what is known for ornidazole: 10.5 +/- 1.7 h. The results confirm that for the molecules weakly bound to protein which "concentrate" in the gastric secretion, the aspiration is an important route of elimination.