Bioavailability and efficacy of omeprazole given orally and by nasogastric tube

We compared the bioavailability and the efficacy of omeprazole provided either as encapsulated enteric-coated granules or as enteric-coated granules delivered via a nasogastric tube in 10 healthy subjects. Omeprazole reduced mean pentagastrin-stimulated peak gastric acid secretion by 85.5% +/- 23.7% when delivered orally and by 79.6% +/- 32.1% when delivered by nasogastric tube; the mean plasma omeprazole concentration area under the curve (AUG) was 2.02 +/- 0.79 after oral delivery and 1.74 +/- 1.89 after nasogastric tube delivery. There was no significant difference in these parameters between the two routes of administration, and there was excellent intrasubject correlation between oral and nasogastric percent acid suppression and AUC. There was a close correlation between AUC and percent acid suppression at AUC values below 0.6, and complete acid suppression at AUC values above 0.6, regardless of the delivery route. We conclude that omeprazole delivered as enteric-coated granules via nasogastric tube provides equal bioavailability and gastric acid suppression as omeprazole given orally in its proprietary formulation.