Effects of orally administered enteric-coated omeprazole on gastric acid secretion in horses.
OBJECTIVE
To determine the effects of orally administered omeprazole, as enteric-coated capsules, on baseline and stimulated gastric acid secretion in horses.


METHODS
5 healthy 8-year-old mixed-breed horses fitted with gastric cannulas.


METHODS
Enteric-coated granules of omeprazole were mixed with corn syrup and administered orally once daily for 5 consecutive days. On days 1 and 5 beginning 5 hours after omeprazole administration, 4 gastric fluid samples were collected, each for 15 minutes, via the gastric cannula (baseline samples). Pentagastrin was administered IV as a constant infusion for the subsequent 2 hours, and 15-minute gastric fluid samples were again collected (stimulated samples). Fluid volume, acidity (mmol H-/L), and pH and gastric acid production (mmol H+) were determined for all baseline samples and for stimulated samples collected during the second hour of pentagastrin infusion. Control experiments were done in a similar manner after giving corn syrup alone to the same horses.


RESULTS
Compared with values obtained during control experiments, baseline and stimulated gastric fluid acidity and gastric acid production significantly decreased, and the mean pH of gastric fluid samples significantly increased, after horses were given 5 daily doses of omeprazole.


CONCLUSIONS
Enteric-coated omeprazole (1.0 mg/kg of body weight; PO) administered once daily for 5 days significantly inhibited unstimulated and pentagastrin-stimulated gastric acid secretion in horses. This commercially available formulation of omeprazole may be efficacious in the treatment of gastroduodenal ulcers in horses.
Andrews
F M
FM
Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville 37901-1071, USA.
Doherty
T J
TJ
Blackford
J T
JT
Nadeau
J A
JA
Saxton
A M
AM
D000284:Administration, Oral; D000818:Animals; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005745:Gastric Acidity Determination / Q000662:veterinary; D005750:Gastric Juice / Q000378:metabolism*; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D006863:Hydrogen-Ion Concentration; D009853:Omeprazole / Q000008:administration & dosage / Q000627:therapeutic use*; D010418:Pentagastrin / Q000378:metabolism; D014677:Pharmaceutical Vehicles; D012016:Reference Values; D013272:Stomach Diseases / Q000188:drug therapy / Q000662:veterinary*; D013608:Tablets, Enteric-Coated
D000897:Anti-Ulcer Agents; D014677:Pharmaceutical Vehicles; D013608:Tablets, Enteric-Coated; D010418:Pentagastrin; D009853:Omeprazole