Effects of Intravenously Administrated Omeprazole on Gastric Juice pH and Gastric Ulcer Scores in Adult Horses

Abstract

The study was performed to evaluate the efficacy of omeprazole powder in sterile water, administered intravenously, on gastric juice pH in adult horses with naturally occurring gastric ulcers. Omeprazole (0.5 mg/kg, IV) was administered once daily for 5 days to 6 adult horses with gastric ulcers. Gastric juice was aspirated through the biopsy channel of an endoscope and pH was measured before and 1 hour after administration of omeprazole on day 1, and then before and after administration of omeprazole on day 5. Gastric ulcer scores were recorded on day 1 before administration of omeprazole and on day 5, 23 hours after the 4th daily dose. Gastric juice pH and ulcer scores were compared between the times. When compared with the pre-injection value (2.01 +/- 0.42), mean +/- SD gastric juice pH was significantly higher when measured 1 hour after administration of the initial dose (4.35 +/- 2.31), and before (5.27 +/- 1.74) and 1 hour after (7.00 +/- 0.25) administration of omeprazole on day 5. Nonglandular gastric ulcer number score significantly decreased from a mean +/- SD of 3.2 +/- 0.80 to 2.0 +/- 1.1, but nonglandular gastric ulcer severity score remained the same. Few glandular ulcers were seen in the study, and scores did not change. Because of its potent and long duration of action on gastric juice pH, this intravenous formulation of omeprazole may show promise for treatment of equine gastric ulcer syndrome (EGUS) in horses with dysphagia, gastric reflux, or other conditions that restrict oral intake of omeprazole paste. Aspiration of gastric juice and measurement of pH can be of use to determine whether the desired pH > 4.0 has been reached after omeprazole treatment.

Evaluation of a wireless ambulatory capsule (SmartPill®) to measure gastrointestinal tract pH, luminal pressure and temperature, and transit time in ponies

“…These data are similar to gastric juice pH values reported in horses [10,12,13]. Gastric pH measured by the capsule ranged from 0.8 to 6.9.…”

Effects of transportation on gastric pH and gastric ulceration in mares

“…During confinement, horses had GF of low pH for the duration of study part 1 (median values of 1.7‐2.49), as expected, and these horses did not have increased gastric squamous ulcer scores. Partitioning of gastric content may influence pH determination in horses, but gastric emptying was similarly complete for horses with indwelling NGT after both confinement and transportation (T1). In the nearly complete absence of retained ingesta, aspiration of GF through the NGT and endoscope was relatively simple, and no differences were observed between samples obtained simultaneously via either NGT or endoscope, including endoscopically observed aspiration through the NGT, suggesting no partitioning of gastric content occurred.…”

Rethinking equine gastric ulcer syndrome: Part 2 – Equine squamous gastric ulcer syndrome (ESGUS)

“…; Andrews et al . ), it is widely believed that once daily administration of omeprazole results in 24 h of acid suppression. However, the methodology used to measure gastric acidity in those studies may not be truly reflective of mucosal pH (Merritt et al .…”