Duration of Antisecretory Effects of Oral Omeprazole in Horses with Chronic Gastric Cannulae
Eight female horses with chronic gastric cannulae were given omeprazole as enteric-coated granules (1.4 mg/kg bwt) via nasogastric tube once daily for 6 days. The effects on basal and pentagastrin-stimulated gastric acid secretion were determined 5 h after dosing on Days 1 and 5 ofadministration. A third gastric secretion test was done on Day 7, 24 h after the dose on Day 6. Gastric juice volume, pH, acidity, and acid output were determined during a 1-h basal secretion test followed by a 2-h pentagastrin-stimulated (6 μg kg−1 h−1) test.
When compared with placebo controls, omeprazole significantly inhibited basal gastric acid output by 72% and pentagastrin-stimulated acid output by 86% on Day 5. Gastric juice pH was also significantly increased. On Day 7, basal gastric acid output was significantly decreased by 90% and pentagastrin-stimulated secretion was decreased by 72%. The effect of omeprazole administration on gastric juice volume was variable.
Once daily administration of 1.4 mg omeprazole/kg bwt significantly inhibited basal and stimulated gastric acid secretion in horses by the 5th dose. Gastric acid secretion was significantly inhibited for at least 27 h after omeprazole treatment, indicating a long duration of antisecretory effect of the drug in horses.
Christine C. Jenkins, James T. Blackford, F. Andrews, Donita L. Frazier, H. Mattsson, S. G. Olovsson, and A. Peterson. "Duration of Antisecretory Effects of Oral Omeprazole in Horses with Chronic Gastric Cannulae" Equine Veterinary Journal 24.S13 (1992): 89-92.